Antinuclear antibodies in sera of patients with recurrent pregnancy wastage Ling Xu, MD, Victoria Chang, BS, Ana Murphy, MD, John A. Rock, MD, Marian Damewood, MD, William SchIaff, MD, and Howard A. Zacur, MD, PhD Baltimore, Maryland Four groups of women were studied to determine whether low-level antinuclear antibody titers are associated with a higher risk for pregnancy loss. Group A consisted of 30 patients with a history of unexplained fetal losses. Group B consisted of 30 women with "explained" fetal losses (e.g., uterine septum or luteal phase defect). Ages and number of losses were comparable between the women in groups A and B. Group C consisted of 61 healthy pregnant women. Group D involved 61 healthy nonpregnant women of reproductive age. In groups A and B, 40% and 53.3% of the respective patients had antinuclear antibody titers 2:1 : 40. In groups C and D the frequencies of positive antinuclear antibody titers were 8.2% and 5.6%, respectively. This study demonstrates a high prevalence of low-titer antinuclear antibody-positive serum in patients with explained and unexplained pregnancy losses. (AM J OBSTET GVNECOL 1990;163:1493-7.)
Key words: Repeated pregnancy wastage or losses, habitual abortion, antinuclear antibody
Recurrent fetal wastage is common in women with systemic lupus erythematosus,'-3 presenting even before the onset of clinical manifestations. 1 . 5 Since antinuclear antibodies have been accepted as serologic markers for the presence of autoimmune disease,6-H the association between recurrent fetal wastage and serum antinuclear antibodies, especially in women who are asymptomatic of any autoimmune disease, has been investigated. No clear relationship has been established until recently when Garcia-De La Torre et al. 9 reported a 30% prevalence of antinuclear antibody-positive sera in patients with unexplained habitual abortions that was significantly greater than 6.6% prevalence in their control group with normal pregnancies. Cowchock et al. 'O reported positive antinuclear antibody titers in four of 14 patients with idiopathic habitual abortion but in only one of 16 patients whose repeated abortions had an explanation (i.e., uterine anomalies, chromosome abnormalities, or luteal phase defect). In a recent prospective study Farnam et al. II reported that the inciFrom the Division of Reproductive Endocrinology, Department of Gynecology and Obstetrics, The johns Hopkins University School of Medicine. Supported in part by National Institutes of Health grant Nos. N01HD-32816 and 5P30HD06268-16. Presented as a poster abstract at the Thirty-sixth Annual Meeting of the Society for Gynecologic Investigation, San Diego, California, March 15-18, 1989. Received for publication january 24,1990; revised june 4,1990; accepted july 16,1990. Reprint requests: Howard A. Zacur, MD, PhD, Park B2-202A, The Johns Hopkins Hospital, 600 North Wolfe St., Baltimore, MD 21205. 6/1/23820
dence of positive antinuclear antibody titers in pregnant women is significantly higher than in nonpregnant women and reaches its highest level at the end of pregnancy. To determine whether positive antinuclear antibody titers are associated with a higher risk of recurrent fetal wastage or a physiologic change in normal pregnancy, we conducted a study to compare the prevalance of antinuclear antibody titers among patients with unexplained recurrent fetal wastage, patients with explained recurrent fetal wastage, women with normal pregnancy, and healthy nonpregnant women.
Material and methods Subjects Patient population. Patients in this study were referred to The Johns Hopkins Hospital from August 1984 to November 1987 for evaluation after at least two consecutive pregnancy losses. Clinical and laboratory evaluation in all patients included antinuclear antibody measurement, karyotypic analysis, hysteroscopy or hysterosalpingography, endometrial biopsy or progesterone determinations, and cervical cultures. Thyroid function studies, activated partial thromboplastin time, anticardiolipin panel, mixed lymphocyte culture, or human leukocyte antigen typing were not performed in all patients. Thirty patients (group A) were identified as having unexplained recurrent fetal wastage because clinical and laboratory evaluation failed to reveal any cause for their pregnancy losses. The mean age of the group was 32.6 years (range, 21 to 38 years). The mean number 1493
1494 Xu et al.
November 1990 Am J Obstet Gynecol
Significance was determined at a probability level of 0.05 for two-tailed test.
Table I. Possible causes of pregnancy losses in patients with repeated pregnancy losses Causes
No.
Uterine abnormality Luteal phase defect Chromosome abnormality Positive cervical culture H yperprolactinemia Adrenal hyperplasia Two or more causes combined
16 6 1
TOTAL
1 1 1
4
30
of pregnancy losses was 3.3 (range, 2 to 14). No patient had a history of autoimmune disease. Another 30 patients (group B) were identified as having explained repeated pregnancy losses because their clinical and laboratory evaluation showed one or more of the following diagnoses: uterine abnormalities, chromosome abnormalities, luteal phase defects, positive cervical culture, or other endocrine and metabolic disorders (Table I). The mean age of this group was 30.4 years (range, 24 to 38 years), and the mean number of pregnancy losses was 2.8 (range, 2 to 6). None had a history of known autoimmune disease. Normal pregnant population. Serum samples from 61 healthy pregnant women were obtained during routine prenatal visits to the obstetric clinic at The Johns Hopkins Hospital (group C). The mean age of this group was 23.2 years (range, 14 to 35 years). Eighteen women were in their first or second trimester, and 43 were in the third trimester of pregnancy when studied. Individuals with a known history of autoimmune disease were not included in this group. Healthy nonpregnant population (control grouP). Sixtyone healthy nonpregnant women of reproductive age (15 to 40 years) were studied (group D). They were considered healthy because none of them had a history of known autoimmune diseases, metabolic disorders, or any chronic or current infectious diseases. These patients had been recruited for another clinical study of oral contraceptive therapy that had been approved by The Johns Hopkins Hospital Joint Committee on Clinical Investigation. None of these patients were taking oral contraceptives at the time of baseline blood sampling. Antinuclear antibody determination. An indirect fluorescent antibody technique using HEp-2 cell culture and reagents supplied by Zeus Scientific, Inc. (Raritan, N.J.) was used for the antinuclear antibody screening. Sera with 1 + or greater fluorescence at a dilution of 1 : 40 were considered positive. Statistical analysis. Statistical analysis was performed with the use of t tests for differences between means, and the use of X· statistic with correction for continuity.
Results
Table II demonstrates the frequency of antinuclear antibody-positive sera in each study group. The frequency of positive antinuclear antibody titers in sera of 30 patients with unexplained repeated pregnancy losses was 40% in comparison with only 5% in 61 healthy nonpregnant women. This difference was statistically significant (X· = 15.19, df = 1, P < 0.01). The frequency of antinuclear antibody-positive sera in 30 patients with explained repeated pregnancy losses was 53%; this incidence was also significantly different from the control group (X· = 25.42, df = 1, P < 0.01). No significant difference in the frequency of antinuclear antibody-positive sera between patients with explained or unexplained pregnancy losses was found. The mean age and mean frequency of pregnancy losses were also compared between antinuclear antibody-positive patients and antinuclear antibody-negative patients in both explained and unexplained recurrent fetal wastage groups. No significant differences were found (Table III). In the group of 61 healthy pregnant women (group C) the frequency of antinuclear antibody-positive sera was 8%. Table II shows that there was no significant difference in the frequency of antinuclear antibodypositive sera between normal pregnant women and healthy nonpregnant women (group D) (X· = 0.4, df = 1, p> 0.05). Gestational age did not correlate with antinuclear antibody-positive sera (Table IV). Comparison of antinuclear antibody-positive sera between nonpregnant women, pregnant control women, women with unexplained repeated pregnancy losses, and explained pregnancy losses showed no effect of age (Tables III and V). Comment
It has been recognized that women with autoimmune disease have an increased frequency of pregnancy losses. The recognition of this association has led to general recommendations to screen patients with recurrent fetal wastage for autoimmunity. Reports on the association between recurrent fetal wastage and positive antinuclear antibody titers from several recent studies are controversial. In this study four population groups were examined for the frequency of antinuclear antibody-positive sera, and the differences among these groups in terms of antinuclear antibody-positive sera were compared. The question of whether recurrent fetal wastage is associated with certain autoimmune disorders has been investigated. Garcia-De La Torre et al. 9 reported that the prevalence of antinuclear antibodies was signifi-
Antinuclear antibodies and pregnancy losses
Volume 163 Number 5, Part 1
1495
Table II. Frequency of antinuclear antibody-positive sera in each study group Antinuclear antibodypositive*
I
%
Groups
No.
n
Normal control Normal pregnancy Explained recurrent fetal wastage Unexplained recurrent fetal wastage
61 61 30
3 5 16
5.6 8.2 53.3
P> P
Key words: Repeated pregnancy wastage or losses, habitual abortion, antinuclear antibody
Recurrent fetal wastage is common in women with systemic lupus erythematosus,'-3 presenting even before the onset of clinical manifestations. 1 . 5 Since antinuclear antibodies have been accepted as serologic markers for the presence of autoimmune disease,6-H the association between recurrent fetal wastage and serum antinuclear antibodies, especially in women who are asymptomatic of any autoimmune disease, has been investigated. No clear relationship has been established until recently when Garcia-De La Torre et al. 9 reported a 30% prevalence of antinuclear antibody-positive sera in patients with unexplained habitual abortions that was significantly greater than 6.6% prevalence in their control group with normal pregnancies. Cowchock et al. 'O reported positive antinuclear antibody titers in four of 14 patients with idiopathic habitual abortion but in only one of 16 patients whose repeated abortions had an explanation (i.e., uterine anomalies, chromosome abnormalities, or luteal phase defect). In a recent prospective study Farnam et al. II reported that the inciFrom the Division of Reproductive Endocrinology, Department of Gynecology and Obstetrics, The johns Hopkins University School of Medicine. Supported in part by National Institutes of Health grant Nos. N01HD-32816 and 5P30HD06268-16. Presented as a poster abstract at the Thirty-sixth Annual Meeting of the Society for Gynecologic Investigation, San Diego, California, March 15-18, 1989. Received for publication january 24,1990; revised june 4,1990; accepted july 16,1990. Reprint requests: Howard A. Zacur, MD, PhD, Park B2-202A, The Johns Hopkins Hospital, 600 North Wolfe St., Baltimore, MD 21205. 6/1/23820
dence of positive antinuclear antibody titers in pregnant women is significantly higher than in nonpregnant women and reaches its highest level at the end of pregnancy. To determine whether positive antinuclear antibody titers are associated with a higher risk of recurrent fetal wastage or a physiologic change in normal pregnancy, we conducted a study to compare the prevalance of antinuclear antibody titers among patients with unexplained recurrent fetal wastage, patients with explained recurrent fetal wastage, women with normal pregnancy, and healthy nonpregnant women.
Material and methods Subjects Patient population. Patients in this study were referred to The Johns Hopkins Hospital from August 1984 to November 1987 for evaluation after at least two consecutive pregnancy losses. Clinical and laboratory evaluation in all patients included antinuclear antibody measurement, karyotypic analysis, hysteroscopy or hysterosalpingography, endometrial biopsy or progesterone determinations, and cervical cultures. Thyroid function studies, activated partial thromboplastin time, anticardiolipin panel, mixed lymphocyte culture, or human leukocyte antigen typing were not performed in all patients. Thirty patients (group A) were identified as having unexplained recurrent fetal wastage because clinical and laboratory evaluation failed to reveal any cause for their pregnancy losses. The mean age of the group was 32.6 years (range, 21 to 38 years). The mean number 1493
1494 Xu et al.
November 1990 Am J Obstet Gynecol
Significance was determined at a probability level of 0.05 for two-tailed test.
Table I. Possible causes of pregnancy losses in patients with repeated pregnancy losses Causes
No.
Uterine abnormality Luteal phase defect Chromosome abnormality Positive cervical culture H yperprolactinemia Adrenal hyperplasia Two or more causes combined
16 6 1
TOTAL
1 1 1
4
30
of pregnancy losses was 3.3 (range, 2 to 14). No patient had a history of autoimmune disease. Another 30 patients (group B) were identified as having explained repeated pregnancy losses because their clinical and laboratory evaluation showed one or more of the following diagnoses: uterine abnormalities, chromosome abnormalities, luteal phase defects, positive cervical culture, or other endocrine and metabolic disorders (Table I). The mean age of this group was 30.4 years (range, 24 to 38 years), and the mean number of pregnancy losses was 2.8 (range, 2 to 6). None had a history of known autoimmune disease. Normal pregnant population. Serum samples from 61 healthy pregnant women were obtained during routine prenatal visits to the obstetric clinic at The Johns Hopkins Hospital (group C). The mean age of this group was 23.2 years (range, 14 to 35 years). Eighteen women were in their first or second trimester, and 43 were in the third trimester of pregnancy when studied. Individuals with a known history of autoimmune disease were not included in this group. Healthy nonpregnant population (control grouP). Sixtyone healthy nonpregnant women of reproductive age (15 to 40 years) were studied (group D). They were considered healthy because none of them had a history of known autoimmune diseases, metabolic disorders, or any chronic or current infectious diseases. These patients had been recruited for another clinical study of oral contraceptive therapy that had been approved by The Johns Hopkins Hospital Joint Committee on Clinical Investigation. None of these patients were taking oral contraceptives at the time of baseline blood sampling. Antinuclear antibody determination. An indirect fluorescent antibody technique using HEp-2 cell culture and reagents supplied by Zeus Scientific, Inc. (Raritan, N.J.) was used for the antinuclear antibody screening. Sera with 1 + or greater fluorescence at a dilution of 1 : 40 were considered positive. Statistical analysis. Statistical analysis was performed with the use of t tests for differences between means, and the use of X· statistic with correction for continuity.
Results
Table II demonstrates the frequency of antinuclear antibody-positive sera in each study group. The frequency of positive antinuclear antibody titers in sera of 30 patients with unexplained repeated pregnancy losses was 40% in comparison with only 5% in 61 healthy nonpregnant women. This difference was statistically significant (X· = 15.19, df = 1, P < 0.01). The frequency of antinuclear antibody-positive sera in 30 patients with explained repeated pregnancy losses was 53%; this incidence was also significantly different from the control group (X· = 25.42, df = 1, P < 0.01). No significant difference in the frequency of antinuclear antibody-positive sera between patients with explained or unexplained pregnancy losses was found. The mean age and mean frequency of pregnancy losses were also compared between antinuclear antibody-positive patients and antinuclear antibody-negative patients in both explained and unexplained recurrent fetal wastage groups. No significant differences were found (Table III). In the group of 61 healthy pregnant women (group C) the frequency of antinuclear antibody-positive sera was 8%. Table II shows that there was no significant difference in the frequency of antinuclear antibodypositive sera between normal pregnant women and healthy nonpregnant women (group D) (X· = 0.4, df = 1, p> 0.05). Gestational age did not correlate with antinuclear antibody-positive sera (Table IV). Comparison of antinuclear antibody-positive sera between nonpregnant women, pregnant control women, women with unexplained repeated pregnancy losses, and explained pregnancy losses showed no effect of age (Tables III and V). Comment
It has been recognized that women with autoimmune disease have an increased frequency of pregnancy losses. The recognition of this association has led to general recommendations to screen patients with recurrent fetal wastage for autoimmunity. Reports on the association between recurrent fetal wastage and positive antinuclear antibody titers from several recent studies are controversial. In this study four population groups were examined for the frequency of antinuclear antibody-positive sera, and the differences among these groups in terms of antinuclear antibody-positive sera were compared. The question of whether recurrent fetal wastage is associated with certain autoimmune disorders has been investigated. Garcia-De La Torre et al. 9 reported that the prevalence of antinuclear antibodies was signifi-
Antinuclear antibodies and pregnancy losses
Volume 163 Number 5, Part 1
1495
Table II. Frequency of antinuclear antibody-positive sera in each study group Antinuclear antibodypositive*
I
%
Groups
No.
n
Normal control Normal pregnancy Explained recurrent fetal wastage Unexplained recurrent fetal wastage
61 61 30
3 5 16
5.6 8.2 53.3
P> P
