Frequency of non-hormonal contraception around conception and association with congenital malformations in offspring

Timing of conception and the risk of spontaneous abortion among pregnancies occurring during the use of natural family planning

OBJECTIVE

Our purpose was to ascertain the effects of timing of conception on the risk of spontaneous abortion.

STUDY DESIGN

To assess these effects, women who conceived while using natural family planning were identified in five centers worldwide between 1987 and 1993. Timing of conception was determined from 868 natural family planning charts that recorded day of intercourse and indices of ovulation (cervical mucus peak obtained according to the ovulation method and/or basal body temperature). Conceptions on days - 1 or 0 with respect to the natural family planning estimated day of ovulation were considered to be "optimally timed," and all other conceptions were considered as "non-optimally timed." The rate of spontaneous abortions per 100 pregnancies was examined in relation to timing of conception, ages, reproductive history, and other covariates with bivariate and multivariate statistical methods.

RESULTS

There were 88 spontaneous abortions among 868 pregnancies (10.1%). The spontaneous abortion rate was similar for 361 optimally timed conceptions (9.1%) and 507 non-optimally timed conceptions (10.9%). However, among 171 women who had experienced a spontaneous abortion in a prior pregnancy, the rate of spontaneous abortion in the index pregnancy was significantly higher with non-optimally timed conceptions (22.6%) as compared with optimally timed conceptions (7.3%). This association was not observed among 697 women with no history of pregnancy loss. The adjusted relative risk of spontaneous abortion among women with non-optimally timed conceptions and a history of pregnancy loss was 2.35 (95% confidence intervals 1.42 to 3.89). The excess risk of spontaneous abortion was observed with both preovulatory and postovulatory conceptions.

CONCLUSIONS

Overall, there is no excess risk of spontaneous abortion among the pregnancies conceived during natural family planning use. However, among women with a history of pregnancy loss, there is an increased risk of spontaneous abortion associated with preovulatory or postovulatory delayed conceptions.

Decreased teratogen susceptibility in mouse fetuses obtained from delayed mating

We examined whether the susceptibility of fetuses to a teratogen differs between fetuses from delayed mating and those from normal mating. Mitomycin-C (MMC; 2.5 mg/kg or 5.0 mg/kg) was administered to pregnant mice intraperitoneally on day 10 of gestation after either normal or delayed mating (6 h). The incidence of MMC-induced malformations in fetuses from delayed mating was significantly lower than in those from the normal mating group when the treatment time was adjusted to be at the same critical period according to the "catch-up" phenomenon of developmental progression in the delayed mating group.

Fertility after contraception or abortion

There is a very small correlation, if any, between the prior use of OCs and congenital malformations, including Down's syndrome. There are few, if any, recent reports on masculinization of a female fetus born to a mother who took an OC containing 1 mg of a progestogen during early pregnancy. However, patients suspected of being pregnant and who are desirous of continuing that pregnancy should not continue to take OCs, nor should progestogen withdrawal pregnancy tests be used. Concern still exists regarding the occurrence of congenital abnormalities in babies born to such women. The incidence of postoperative infection after first trimester therapeutic abortion in this country is low. However, increasing numbers of women are undergoing repeated pregnancy terminations, and their risk for subsequent pelvic infections may be multiplied with each succeeding abortion. The incidence of prematurity due to cervical incompetence or surgical infertility after first trimester pregnancy terminations is not increased significantly. Asherman's syndrome may occur after septic therapeutic abortion. The pregnancy rate after treatment of this syndrome is low. The return of menses and the achievement of a pregnancy may be slightly delayed after OCs are discontinued, but the fertility rate is within the normal range by 1 year. The incidence of postpill amenorrhea of greater than 6 months' duration is probably less than 1%. The occurrence of the syndrome does not seem to be related to length of use or type of pill. Patients with prior normal menses as well as those with menstrual abnormalities before use of OCs may develop this syndrome. Patients with normal estrogen and gonadotropin levels usually respond with return of menses and ovulation when treated with clomiphene. The rate for achievement of pregnancy is much lower than that for patients with spontaneous return of menses. The criteria for defining PID or for categorizing its severity are diverse. The incidence of PID is higher among IUD users than among patients taking OCs or using a barrier method. The excess risk of PID among IUD users, with the exception of the first few months after insertion, is related to sexually transmitted diseases and not the IUD. Women with no risk factors for sexually transmitted diseases have little increased risk of PID or infertility associated with IUD use. There appears to be no increased risk of congenital anomalies, altered sex ratio, or early pregnancy loss among spermicide users. All present methods of contraception entail some risk to the patient. The risk of imparied future fertility with the use of any method appears to be low.(ABSTRACT TRUNCATED AT 400 WORDS)

Maternal spermicide use and adverse reproductive outcome: a meta-analysis

A meta-analysis was performed to determine whether the literature provides evidence that periconceptual or postconceptual maternal use of spermicides is detrimental to the developing fetus. Nine studies that investigated teratogenicity met the inclusion criteria. The Mantel-Haenszel summary odds ratio was 1.02 (95% confidence interval = 0.78 to 1.32). The chi 2 analyses was 0.10 for significance from unity (p = 0.748) and 8.73 for homogeneity of effects (p = 0.365). Studies comparing specific abnormalities with other abnormalities also indicated no association (odds ratio = 0.96; 95% confidence interval = 0.72 to 1.28). Studies investigating other adverse events (spontaneous abortion, stillbirth, reduced fetal weight, prematurity, or increased incidence of female births) showed similar negative results. Cohen's d, the overall effect size as determined by Tukey's jackknife method, was -0.001 (95% confidence interval = -0.018 to 0.017). These results indicate that maternal use of spermicides is not associated with adverse fetal outcomes. Meta-analysis adds quantitative support for conclusions from traditional reviews of the subject.

Pregnancy outcome associated with natural family planning (NFP): scientific basis and experimental design for an international cohort study

Although natural family planning (NFP) is a form of contraception without ostensible maternal risks (other than pregnancy), potential fetal risks could exist if aging gametes are involved in inadvertent fertilization. In the following report, we first review animal studies firmly establishing that aging sperm and aging oocytes (delayed fertilization) cause chromosomal abnormalities in mammals and other species. We next review human studies associating decreased coital frequency with trisomy and studies of NFP populations that generally show no increased frequency of anomalous offspring or spontaneous abortions. Our rationale for initiating an international cohort study is presented, along with the experimental design selected. Preliminary findings indicate that the experimental design chosen will indeed provide information allowing NFP safety to be assessed definitively.

Spermicide use and pregnancy outcome

The relation between periconceptional vaginal spermicide use and sex ratio at birth, birthweight, and the frequency of congenital anomalies was examined in a cohort of 2,712 New York City obstetric patients, 149 of whom (5.5 per cent) became pregnant while using spermicides or had used spermicides before and after conception. Periconceptional spermicide use was not associated with any important variation in the expected sex ratio at birth, nor with major or minor congenital anomalies. Exposure to spermicides in the periconceptional period, defined dichotomously as present or absent, was not associated with decreased birthweight in male or female infants. There was a slight decrease in birthweight among female infants with increasing duration of postconceptional spermicide use; an estimated 7.4 grams decrease with each day of use. The size of the effect and its selectivity by sex suggest a chance finding.

Incidence and aetiology of hydatidiform mole: an epidemiological review

Epidemiological investigation of the incidence and aetiology of hydatidiform mole (HM) is receiving increasing attention. Recent, population-based studies suggest that earlier reports of a very high incidence of HM in Asia, Africa and South-Central America may have been exaggerated, due primarily to selection bias in patients studied at university hospitals. Japanese population studies indicate a two-fold higher rate of HM compared with Caucasian rates but Chinese rates appear to be similar. Population studies presently available suggest a worldwide range of HM somewhere between 0.5 and 2.5/1000 pregnancies. When deliveries form the rate denominator the rates are somewhat higher, depending primarily on the national rate of induced abortions. The independent effects on incidence of geographic locale, ethnicity and socio-cultural factors have not been adequately disentangled although the genetic studies suggest ethnicity might be the predominant variable. Maternal age is the most consistently demonstrated risk factor; teenagers and, especially, women over age 35 being at increased risk. The independent effects of paternal age and pregnancy history are not established. Women with a history of one HM seem to have a ten-fold risk of repeat HM compared with women who have no history of HM. Aetiological studies have not revealed any environmental risk factor for which there is unequivocal agreement about its influence on HM. New case-control studies of HM aetiology must classify HM according to genetic aetiology. Cohort studies are required to explore more fully the relation of HM to malignant sequelae.

Maternal exposure to spermicides in relation to certain birth defects

Several studies have found no increase in the overall frequency of birth defects in association with the use of spermicides, but the possibility of an increase in specific defects remains. We evaluated this possibility in a large case-control study. Infants with certain malformations (265 with Down's syndrome, 396 with hypospadias, 146 with limb reduction defects, 116 with neoplasms, and 215 with neural-tube defects) were compared with 3442 control infants with a wide variety of other defects. Exposure to spermicides was assessed for three periods: use during the periconceptional period (one month before through one month after the last menstrual period), use during the first trimester (the first four lunar months of pregnancy), and any use during the lifetime. For the five groups of cases and for each interval, the odds ratios were close to 1.0 (range, 0.7 to 1.3); the upper 95 percent confidence bounds were 2.2 or lower. Risks did not increase with the duration of exposure. When each of the active ingredients in currently available spermicides was considered separately, no differences in odds ratios were apparent between the types of spermicides. With the possible exception of a subgroup of cases (limb reduction defects of unknown cause), these results suggest that risks for the five specific birth defects evaluated are not increased by exposure to spermicides.

Lack of association between spermicide use and trisomy

It has been suggested that the maternal use of spermicidal contraceptives increases the frequency of certain congenital anomalies, including trisomy, but this issue is in dispute. This controversy led us to examine whether the use of spermicidal contraceptives is associated with an increased risk of fetal trisomy. A questionnaire concerning contraceptive use was completed by 13,729 women who were undergoing prenatal fetal chromosome studies but were as yet unaware of the results. Most women were at increased risk of having a trisomic fetus because of their advanced age. Of 154 fetuses with trisomy, 98 had trisomy 21. For each woman (case) with an affected fetus, four controls were selected from among women with chromosomally normal fetuses, matched for maternal age and medical center. Cases and controls were compared by matched-sample maximum-likelihood logistic regression, to examine the association between fetal trisomy and four measures of spermicide use: periconceptional use, timing of last use, duration of last use, and total lifetime use. No evidence was found for an association, either when all types of trisomy were combined or when trisomy 21 alone was considered. All point estimates of odds ratios relating spermicidal exposure to trisomy were approximately 1, and an effect greater than a twofold increase was excluded with 95 percent confidence in the combined-trisomy group for all measures of spermicide use.

"Proof" of cause and effect in epidemiologic studies: criteria for judgment

A review of epidemiologic criteria for judging cause and effect emphasizes their empirical basis and points to their limitations for establishing "scientific proof." The criteria are applied to a controversy concerning a putative detrimental effect of spermicides on spontaneous abortion and congenital malformations. The criteria indicate a lack of firm evidence for the contention that spermicides have an adverse effect on pregnancy outcome.

Spermicidal contraceptives and poor reproductive outcomes: the epidemiologic evidence against an association

The first widely publicized report of an association between spermicidal contraception and congenital malformations and spontaneous abortion had considerable impact on obstetric practice. A large number of more recent epidemiologic studies have generally failed to support the earlier finding, and it is concluded that no such association has been demonstrated. The available evidence precludes the need for additional regulation of spermicidal contraception.

Aged gametes, adverse pregnancy outcomes and natural family planning. An epidemiologic review

Unconfirmed epidemiologic studies suggest a possible increased risk of birth defects associated with Natural Family Planning (NFP) use, and an increased incidence of spontaneous abortion or frequency of chromosomal abnormalities in abortuses associated with conceptions outside the most "fertile period". The risk is approximately two- to four-fold, but the evidence is by no means conclusive. The implication for NFP depends on the frequency of method failures in user populations, but is not likely to constitute a major hazard. Further research could utilize a data bank of NFP charts.

Previous experience of induced abortion as a risk factor for fetal death and preterm delivery

As part of a community-based study in Korea to evaluate the effects of previous induced abortion on length of gestation and pregnancy outcome of subsequent pregnancies, we analyzed data obtained from January 1979 to December 1981 on pregnancies reported to family health workers in Kang Hwa Island, Korea. The preterm, live-birth rates were not significantly associated with previous induced abortion. Overall, the life table-estimated fetal death rate for women enrolled at the eighth or earlier weeks of gestation was 13.7%, 10.2% for women with no previous induced abortion and 28.9% for women with previous induced abortion. The relative risk for fetal death for women who had undergone a previous abortion was 2.8; relative risk for parous women compared to nulliparous women was 3.4. After controlling for parity, previous induced abortion was not a significant variable for fetal death rate.