CASE REPORT
Rupture of rudimentary horn pregnancy JONG-CHOU CHANG, YIH-CHI LIN From the Department of Obstetrics & Gynecology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, R.O.C.
Actu Ohstet Gynecol Scand 1YY2; 71: 235-238
A rare case of rupture of an noncommunucating rudimentary horn pregnancy is reported. The pregnancy proceeded to 25 gestational weeks, when the rudimentary horn ruptured. The patient had signs and symptoms of massive hemoperitoneurn. An emergency exploratory laparotomy revealed rupture of the gravid rudimentary horn and the fetus was lying free in the peritoneal cavity, was delivered breech and died 2 hours later. This reproductive complication was treated successfully by prompt exploratory laparotomy. Some of the factors associated with pregnancy in a rudimentary horn are discussed. Key words: rudimentary horn pregnancy; uterine rupture Submitted April 4, 199I Accepted January 13. 1992
Pregnancy in the rudimentary horn is an extremely rare form of ectopic gestation with an incidence of 1: 100,000 of all pregnancies (1). Less than 5% of the reported cases have been diagnosed preoperatively (2). As early as 1669 Maunceau and Vassal (quoted by Muslow) (3) reported a case of pregnancy in a rudimentary uterine horn causing rupture. Most of the early cases were diagnosed at autopsy after maternal death resulting from intraperitoneal hemorrhage. Rudimentary horn is one of the rarest congenital uterine anomalies and consists of a relatively normal appearing uterus on one side with a rudimentary horn on the other (4). The rudimentary horn may consist of a functional cavity, or it may be a small solid lump of the uterine muscle with no functional endometrium. Pregnancy in the rudimentary horn is possible only when transperitoneal migration of either spermatozoa or fertilized ovum from the contralateral side occurs. In 90% of the cases reported, rupture of the rudimentary horn occurred in the second trimester ( 2 ) . On occasion a pregnancy may advance into the third trimester with a viable fetus in an intact horn, o r rarely in the peritoneal cavity as a secondary abdominal pregnancy following rupture. In the past three decades improved diagnostic methods with ultrasound scan (especially transvagi-
nal) may have increased the accuracy of diagnosis. Prompt surgical intervention and availability of blood transfusion have resulted in a lower matenal mortality rate.
Case report A 28 year old primigravida was first seen in our hospital at 11 weeks of gestation for regular prenatal care on June 5, 1990. The vaginal examination revealed the gestational uterus with left adnexal enlargement. Ultrasonographic examination showed double uterus; the pregnancy was in the right uterus and the left uterus was also well-formed compatible with gestational age (Fig. 1). Menarche and subsequent menstrual cycles were regular, and normal, but she had a history of slight dysmenorrhea since menarche. The exact date of last menstrual period was March 24, 1990, compatible with gestational weeks. Her family history was not significant for obstetrical problems. Thereafter, she had visited a peripheral hospital for symptomatic relief of episode of abdominal pain and didn’t appear until she was hospitalized. On September 11,1990, she was transferred to the Department of Obstetrics & Gynecology, Chang Actu Ohstet Gynecol Scand 71 (1992)
236
J-C. Chang and Y-C. Lin
Fig. 1 . Showing double uterus with the pregnancy in the right uterus (RU) in 11 gestational weeks. The photo also shows left uterus (LU).
Gung Memorial Hospital, due to acute pain in her abdomen just after coitus. A t the emergency room, ultrasonography was performed, and revealed a living fetus with moderate oligohydramnios. Fetal bi-parietal diameter (BPD) was 6.2 cm, abdominal conference (AC) was 19.1 crn and femoral length was 3.9 cm, all compatible with 25 weeks gestation. Pelvic examination showed the cervix to be closed, thick and deviated anteriorly to the right. On examination the patient was in a state of hypovolemic shock. She was pale but respiratory and cardiovasclar systems were within normal limits. A coagulation profile was normal. There was marked distension of the abdomen, more so in the lower abdomen. Muscle guarding and rigidity with rebounding pain were present. Both the iliac fossae were tender. Liver and spleen were not palpable. Cullen’s sign was positive. Both iliac fossae and posterior pouch were tender. Uterine size could not be made out clearly. A tentative diagnosis of acute uterine rupture was made, but acute appendicitis was not ruled out. She was in great pain and complained of shoulder pain, but not vaginal bleeding or vomiting. The pain increased and she mentioned that the movements of the fetus aggravated the pain. Blood pressure was 90/50 mmHg. Emergency laparotomy was performed on the diagnosis of intra-abdominal bleeding. The patient was rapidly infused with two bottles of 500 ml of 5% glucose after sending blood for grouping and cross matching. When opening the peritoneum we found the fetus lying free in the peritoneal cavity in about 1500 ml of bloody amniotic/peritoneal fluid with blood clots loosely adhering to the omenturn. The premature, pale newborn was hurried to pediatric intensive care. The female infant weighed 545 gm with Apgar Scores 1 at 1 min., 3 at 5 min., but died 2 hours later. Acta Obstet Gynecol Scand 71 (1992)
Examination of the genital organs showed a rupture of right rudimentary horn of a bicornuate uterus. There was a 8 cm long ragged tear in the lateral wall of the right rudimentary horn which was bleeding. The left horn was continuous with the single cervix and was attached to the right horn by a thin band of connective tissue and a subserosal leiomyoma was found (Fig. 2 & Fig. 3 ) . A normal fallopian tube and ovary were connected to each horn, and the left ovary contained the corpus luteum of pregnancy. A well developed placenta was found attached to the ruptured side on the right rudimentary horn with large spiral vessels. No connection to the uterine cavity of the normal left uterus was proved by metal probe. Accordingly, excision of the right rudimentary horn was carried out together with right salpingoophorectomy. Palpation of the kidneys revealed no abnormalities. As soon as fresh blood was available, 5 units of blood was infused. The postoperative recovery was satisfactory and the patient was discharged on the eighth day after suture removal. The patient was asymptomatic at follow u p one month later. An intravenous pyelogram done later showed normal kidney and urinary tract. Microscopic examination of the removed adnexa revealed a normal tube and ovary. The excised horn displayed acute inflammatory reaction with extensive interstitial fibrosis of the myometrium. Careful sectioning of the fibrous band that connected the two horns failed to show any communication channel.
Fig. 2. Intraoperative photography revealing the right ruptured rudimentary horn (RH), the fibrous connecting band (F) and the normal non-pregnant left uterine horn (LH) with subserosal leiomyoma (M). Arrow shows rupture hole.
Rupture of rudimentary horn pregnancy
Fig. 3 . Schematic drawing of the right rudimentary horn pregnancy (RH) and subserosal leiomyoma (M).
Discussion The first ruptured pregnancy in a rudimentary horn was presented by Mauriceau in 1669 (3). Since then, more than 350 such cases have been reported (1, 3, 5 ) . This is still one of the rarest and most morbid conditions. The majority of pregnancies in the rudimentary horn rupture in the first or second trimester and cause massive intra-abdominal hemorrhage and potentially threaten the mother’s life (2, 6). A rudimentary horn results from an arrest in the development of one of the mullerian ducts and failure to fuse with the other side The connecting band of the rudimentary horn is subject to many variables; it may be muscular or fibrous and pedunculated. T h e communication of this horn to the main uterine cavity is absent in the majority of cases. Kehrer (7) reported noncommunication between uterus and the accessory horn in 78% of his cases and pregnancy in the rudimentary horn can then occur only via transperitoneal migration of the sperm or fertilized ovum. Actually, the corpus luteum is in the opposite ovary in 10% of the cases (2). The pregnancy often sur-
237
vives the first trimester only to terminate by uterine rupture during the fourth or fifth month of gestation. The thickness of the surrounding muscle and the vascular supply are usually enough to hold the pregnancy during the first trimester. In most cases the gestation usually lasts longer than tuba1 pregnancy. However, 8&90% of the cases rupture by the midsecond trimester, and approximately 10% will go to term with a 2% fetal salvage rate (8). In most of the cases, pregnancy in the rudimentary horn often terminates by missed abortion or intrauterine fetal death. Decreased blood supply, limited uterine distensibility and myometrial contractibility are the contributory factors. Live births are rarely recorded (8). Abdominal pain is a typical sign in all reported cases and it has mostly been found in the beginning of the first and second trimester. Recently, ultrasound scanning (especially transvaginal) has become general practice and its use to diagnose rudimentary horn pregnancy has been reported ( 5 , 9). An extrauterine gestation accompanied by a well-defined placenta visible on ultrasound scan is suggested as a criterion for differentiating rudimentary ,horn pregnancy from abdominal pregnancy. The confines of a rudimentary horn, although very thin, tend to delineate the placenta, making it more identifiable; placenta appearance on ultrasound scan may be helpful for early diagnosis. Delay in diagnosis during early pregnancy is quite common as there are no definitesigns to distinquish this abnormal implantation from normal intra-uterine pregnancy, especially if it is anterior to the normal horn. Therefore, it should be taken into consideration, when a pelvic mass is discovered during sonography in a pregnant patient, that it is possible it may be a non-gravid horn of a bicornuate uterus. Once this condition is strongly suspected, the treatment is laparotomy and excision of the rudimentary horn. It generally does not interfere with future reproduction (9). In all such cases an intravenous pyelogram is indicated because of the high incidence of associated urinary tract anomalies in the presence of genital tract anomalies (8).
References 1 . Johansen K . Pregnancy in a rudimentary horn, two case reports. Obstet Gynecol 196Y; 34: 805-8.
2. O’Leary JL, O’Leary JA. Rudimentary horn pregnancy. Obstet Gynecol. 1963; 22: 371-5. 3. Muslow FW, Cedar R . Pregnancy in a rudimentary horn of the uterus. Am J . Obstet Gynecol 1945; 49: 773-6.
4. Heinonen PK, Saarikoski S, Pystynen P. Reproductive Actu Obsrer Gynecol Scand 71 (1992)
l38
J-C.Chang and Y-C.Lin
performance or woman with uterine anomalies. An evaluation of 182 cases. Acta Obstet Gynecol Scand 1982; 61: 15742. Holden R, Hart P. First trimester rudimentary horn pregnancy: prerupture ultrasound diagnosis. Obstet Gynecol 1983; 61: 565-85. Liang ST, Woo JSK, Tang LCH, Wong RLC. Advanced pregnancy in the rudimentary horn of a bicornuate uterus. Acta Obstet Gynecol Scand 1985; 64: 447-9. Kehrer E. Das Nebenhorn des doppelten Uterus (Heidelberg 1980). Rolen AC, Choquette AJ, Semmens JP. Rudimentary
4ctu O h w t Gynecol Srund 71 (1992)
uterine horn: obstetric and gynecologic complications. Obstet Gynecol 1966; 27: 8 0 6 1 3 . 9. Heinonen PK. Clinical imdications of the unicornuate uterus with rudimentary horn. Int J Gynecol Obstet 1983; 21: 145-50.
Address for correspondence. Jong-Chou Chang, M.D. 123 Ta-Pei Road, Niao-Sung Hsiang Kaohsiung Hsien Taiwan. R.O.C.
Rupture of rudimentary horn pregnancy JONG-CHOU CHANG, YIH-CHI LIN From the Department of Obstetrics & Gynecology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, R.O.C.
Actu Ohstet Gynecol Scand 1YY2; 71: 235-238
A rare case of rupture of an noncommunucating rudimentary horn pregnancy is reported. The pregnancy proceeded to 25 gestational weeks, when the rudimentary horn ruptured. The patient had signs and symptoms of massive hemoperitoneurn. An emergency exploratory laparotomy revealed rupture of the gravid rudimentary horn and the fetus was lying free in the peritoneal cavity, was delivered breech and died 2 hours later. This reproductive complication was treated successfully by prompt exploratory laparotomy. Some of the factors associated with pregnancy in a rudimentary horn are discussed. Key words: rudimentary horn pregnancy; uterine rupture Submitted April 4, 199I Accepted January 13. 1992
Pregnancy in the rudimentary horn is an extremely rare form of ectopic gestation with an incidence of 1: 100,000 of all pregnancies (1). Less than 5% of the reported cases have been diagnosed preoperatively (2). As early as 1669 Maunceau and Vassal (quoted by Muslow) (3) reported a case of pregnancy in a rudimentary uterine horn causing rupture. Most of the early cases were diagnosed at autopsy after maternal death resulting from intraperitoneal hemorrhage. Rudimentary horn is one of the rarest congenital uterine anomalies and consists of a relatively normal appearing uterus on one side with a rudimentary horn on the other (4). The rudimentary horn may consist of a functional cavity, or it may be a small solid lump of the uterine muscle with no functional endometrium. Pregnancy in the rudimentary horn is possible only when transperitoneal migration of either spermatozoa or fertilized ovum from the contralateral side occurs. In 90% of the cases reported, rupture of the rudimentary horn occurred in the second trimester ( 2 ) . On occasion a pregnancy may advance into the third trimester with a viable fetus in an intact horn, o r rarely in the peritoneal cavity as a secondary abdominal pregnancy following rupture. In the past three decades improved diagnostic methods with ultrasound scan (especially transvagi-
nal) may have increased the accuracy of diagnosis. Prompt surgical intervention and availability of blood transfusion have resulted in a lower matenal mortality rate.
Case report A 28 year old primigravida was first seen in our hospital at 11 weeks of gestation for regular prenatal care on June 5, 1990. The vaginal examination revealed the gestational uterus with left adnexal enlargement. Ultrasonographic examination showed double uterus; the pregnancy was in the right uterus and the left uterus was also well-formed compatible with gestational age (Fig. 1). Menarche and subsequent menstrual cycles were regular, and normal, but she had a history of slight dysmenorrhea since menarche. The exact date of last menstrual period was March 24, 1990, compatible with gestational weeks. Her family history was not significant for obstetrical problems. Thereafter, she had visited a peripheral hospital for symptomatic relief of episode of abdominal pain and didn’t appear until she was hospitalized. On September 11,1990, she was transferred to the Department of Obstetrics & Gynecology, Chang Actu Ohstet Gynecol Scand 71 (1992)
236
J-C. Chang and Y-C. Lin
Fig. 1 . Showing double uterus with the pregnancy in the right uterus (RU) in 11 gestational weeks. The photo also shows left uterus (LU).
Gung Memorial Hospital, due to acute pain in her abdomen just after coitus. A t the emergency room, ultrasonography was performed, and revealed a living fetus with moderate oligohydramnios. Fetal bi-parietal diameter (BPD) was 6.2 cm, abdominal conference (AC) was 19.1 crn and femoral length was 3.9 cm, all compatible with 25 weeks gestation. Pelvic examination showed the cervix to be closed, thick and deviated anteriorly to the right. On examination the patient was in a state of hypovolemic shock. She was pale but respiratory and cardiovasclar systems were within normal limits. A coagulation profile was normal. There was marked distension of the abdomen, more so in the lower abdomen. Muscle guarding and rigidity with rebounding pain were present. Both the iliac fossae were tender. Liver and spleen were not palpable. Cullen’s sign was positive. Both iliac fossae and posterior pouch were tender. Uterine size could not be made out clearly. A tentative diagnosis of acute uterine rupture was made, but acute appendicitis was not ruled out. She was in great pain and complained of shoulder pain, but not vaginal bleeding or vomiting. The pain increased and she mentioned that the movements of the fetus aggravated the pain. Blood pressure was 90/50 mmHg. Emergency laparotomy was performed on the diagnosis of intra-abdominal bleeding. The patient was rapidly infused with two bottles of 500 ml of 5% glucose after sending blood for grouping and cross matching. When opening the peritoneum we found the fetus lying free in the peritoneal cavity in about 1500 ml of bloody amniotic/peritoneal fluid with blood clots loosely adhering to the omenturn. The premature, pale newborn was hurried to pediatric intensive care. The female infant weighed 545 gm with Apgar Scores 1 at 1 min., 3 at 5 min., but died 2 hours later. Acta Obstet Gynecol Scand 71 (1992)
Examination of the genital organs showed a rupture of right rudimentary horn of a bicornuate uterus. There was a 8 cm long ragged tear in the lateral wall of the right rudimentary horn which was bleeding. The left horn was continuous with the single cervix and was attached to the right horn by a thin band of connective tissue and a subserosal leiomyoma was found (Fig. 2 & Fig. 3 ) . A normal fallopian tube and ovary were connected to each horn, and the left ovary contained the corpus luteum of pregnancy. A well developed placenta was found attached to the ruptured side on the right rudimentary horn with large spiral vessels. No connection to the uterine cavity of the normal left uterus was proved by metal probe. Accordingly, excision of the right rudimentary horn was carried out together with right salpingoophorectomy. Palpation of the kidneys revealed no abnormalities. As soon as fresh blood was available, 5 units of blood was infused. The postoperative recovery was satisfactory and the patient was discharged on the eighth day after suture removal. The patient was asymptomatic at follow u p one month later. An intravenous pyelogram done later showed normal kidney and urinary tract. Microscopic examination of the removed adnexa revealed a normal tube and ovary. The excised horn displayed acute inflammatory reaction with extensive interstitial fibrosis of the myometrium. Careful sectioning of the fibrous band that connected the two horns failed to show any communication channel.
Fig. 2. Intraoperative photography revealing the right ruptured rudimentary horn (RH), the fibrous connecting band (F) and the normal non-pregnant left uterine horn (LH) with subserosal leiomyoma (M). Arrow shows rupture hole.
Rupture of rudimentary horn pregnancy
Fig. 3 . Schematic drawing of the right rudimentary horn pregnancy (RH) and subserosal leiomyoma (M).
Discussion The first ruptured pregnancy in a rudimentary horn was presented by Mauriceau in 1669 (3). Since then, more than 350 such cases have been reported (1, 3, 5 ) . This is still one of the rarest and most morbid conditions. The majority of pregnancies in the rudimentary horn rupture in the first or second trimester and cause massive intra-abdominal hemorrhage and potentially threaten the mother’s life (2, 6). A rudimentary horn results from an arrest in the development of one of the mullerian ducts and failure to fuse with the other side The connecting band of the rudimentary horn is subject to many variables; it may be muscular or fibrous and pedunculated. T h e communication of this horn to the main uterine cavity is absent in the majority of cases. Kehrer (7) reported noncommunication between uterus and the accessory horn in 78% of his cases and pregnancy in the rudimentary horn can then occur only via transperitoneal migration of the sperm or fertilized ovum. Actually, the corpus luteum is in the opposite ovary in 10% of the cases (2). The pregnancy often sur-
237
vives the first trimester only to terminate by uterine rupture during the fourth or fifth month of gestation. The thickness of the surrounding muscle and the vascular supply are usually enough to hold the pregnancy during the first trimester. In most cases the gestation usually lasts longer than tuba1 pregnancy. However, 8&90% of the cases rupture by the midsecond trimester, and approximately 10% will go to term with a 2% fetal salvage rate (8). In most of the cases, pregnancy in the rudimentary horn often terminates by missed abortion or intrauterine fetal death. Decreased blood supply, limited uterine distensibility and myometrial contractibility are the contributory factors. Live births are rarely recorded (8). Abdominal pain is a typical sign in all reported cases and it has mostly been found in the beginning of the first and second trimester. Recently, ultrasound scanning (especially transvaginal) has become general practice and its use to diagnose rudimentary horn pregnancy has been reported ( 5 , 9). An extrauterine gestation accompanied by a well-defined placenta visible on ultrasound scan is suggested as a criterion for differentiating rudimentary ,horn pregnancy from abdominal pregnancy. The confines of a rudimentary horn, although very thin, tend to delineate the placenta, making it more identifiable; placenta appearance on ultrasound scan may be helpful for early diagnosis. Delay in diagnosis during early pregnancy is quite common as there are no definitesigns to distinquish this abnormal implantation from normal intra-uterine pregnancy, especially if it is anterior to the normal horn. Therefore, it should be taken into consideration, when a pelvic mass is discovered during sonography in a pregnant patient, that it is possible it may be a non-gravid horn of a bicornuate uterus. Once this condition is strongly suspected, the treatment is laparotomy and excision of the rudimentary horn. It generally does not interfere with future reproduction (9). In all such cases an intravenous pyelogram is indicated because of the high incidence of associated urinary tract anomalies in the presence of genital tract anomalies (8).
References 1 . Johansen K . Pregnancy in a rudimentary horn, two case reports. Obstet Gynecol 196Y; 34: 805-8.
2. O’Leary JL, O’Leary JA. Rudimentary horn pregnancy. Obstet Gynecol. 1963; 22: 371-5. 3. Muslow FW, Cedar R . Pregnancy in a rudimentary horn of the uterus. Am J . Obstet Gynecol 1945; 49: 773-6.
4. Heinonen PK, Saarikoski S, Pystynen P. Reproductive Actu Obsrer Gynecol Scand 71 (1992)
l38
J-C.Chang and Y-C.Lin
performance or woman with uterine anomalies. An evaluation of 182 cases. Acta Obstet Gynecol Scand 1982; 61: 15742. Holden R, Hart P. First trimester rudimentary horn pregnancy: prerupture ultrasound diagnosis. Obstet Gynecol 1983; 61: 565-85. Liang ST, Woo JSK, Tang LCH, Wong RLC. Advanced pregnancy in the rudimentary horn of a bicornuate uterus. Acta Obstet Gynecol Scand 1985; 64: 447-9. Kehrer E. Das Nebenhorn des doppelten Uterus (Heidelberg 1980). Rolen AC, Choquette AJ, Semmens JP. Rudimentary
4ctu O h w t Gynecol Srund 71 (1992)
uterine horn: obstetric and gynecologic complications. Obstet Gynecol 1966; 27: 8 0 6 1 3 . 9. Heinonen PK. Clinical imdications of the unicornuate uterus with rudimentary horn. Int J Gynecol Obstet 1983; 21: 145-50.
Address for correspondence. Jong-Chou Chang, M.D. 123 Ta-Pei Road, Niao-Sung Hsiang Kaohsiung Hsien Taiwan. R.O.C.
