Cardiovascular birth defects and antenatal exposure to female sex hormones: a reevaluation of some base data

The Impact of Oral Intake of Dydrogesterone on Fetal Heart Development During Early Pregnancy

Congenital heart disease is the most frequent form of congenital anomaly in newborn infants and accounts for more than a quarter of all serious congenital afflictions worldwide. A genetic etiology is identified in <20 % of cases of congenital heart defects, and in most cases the etiology remains a mystery. In the context of the health burden caused by congenital heart disease, the contribution of non-inherited risk factors is important especially if it turns out to be caused by a drug which can be avoided during pregnancy. We sought to determine whether maternal dydrogesterone treatment in early pregnancy is associated with congenital heart disease in the infant. We conducted a retrospective case-control study of birth defects and associated risk factors. Data were obtained and compared between 202 children born with congenital heart disease and a control group consisting of 200 children. All children were born in the period of 2010-2013. Dydrogesterone exposure was defined as any reported use during the first trimester of pregnancy. Exclusion criteria included stillbirths, children with chromosomal abnormalities and infants of mothers with chronic medical illnesses, e.g., diabetes. Binary logistic regression analyses were used to analyze the data and attempt to identify a causal relationship between drug exposure and congenital heart disease. Mothers of children born with congenital heart disease received more dydrogesterone during first trimester of pregnancy than mothers of children in the control group [adjusted odds ratio 2.71; (95 % CI 1.54-4.24); P = 0.001]. We identified a positive association between dydrogesterone usage during early pregnancy and congenital heart disease in the offspring. Nevertheless, further studies are needed to confirm these results.

Embryo–fetal toxicity signals for 17α-hydroxyprogesterone caproate in high-risk pregnancies: A review of the non-clinical literature for embryo–fetal toxicity with progestins

OBJECTIVE

A large National Institutes of Health (NIH) study showed that pharmacy-compounded 17alpha-hydroxyprogesterone caproate (17-OHP-C) reduced the incidence of preterm birth. The study results included a signal that 17-OHP-C may be associated with an increase in the rate of miscarriages and stillbirths. The most probable cause of an increased incidence of miscarriage/stillbirths may be the use of 17-OHP-C in high-risk patients. The current search of the non-clinical literature was performed to identify whether there were any signals from studies in animals that might suggest concerns for the safe use of progestins generally, and 17-OHP-C specifically, in the prevention of preterm birth in humans.

METHODS

An extensive literature search was performed for progesterone, 17-hydroxyprogesterone, and 17-OHP-C, using Medline and Toxline databases, textbooks, and then the obtained publications. Because 17-OHP-C does not have a standardized clinical formulation or optimal route of administration identified, all formulations, vehicles, routes and doses were included in the search, as well as treatment during any stage of pregnancy. All publications obtained were reviewed for relevancy; those in German, French, Italian or Russian were translated.

RESULTS

None of the relevant non-clinical studies conducted in mice, rats, rabbits, guinea pigs, horses or non-human primates met current standards for determining reproductive and developmental effects as part of the process of drug development. Most studies focused on the potential of 17-OHP-C for teratogenicity. Many studies used supra-pharmacologic and/or high multiples of human exposure in their study design. Overall, 17-OHP-C was consistently shown to be less potent than progesterone, and neither progesterone nor 17-OHP-C consistently adversely affected maternal weight, embryo-fetal viability or caused malformations. One study in rhesus monkeys raises concerns because resorption/abortion occurred at the human equivalent dose of 17-OHP-C, 10 mg/kg; this finding did not occur in cynomolgus monkeys. The absence of information regarding the serum levels of both progesterone and 17-OHP-C in the animal studies and in humans, as well as presumed inter-species metabolic differences, make it difficult to conclude that the findings with 17-OHP-C in rhesus monkeys and the signal in the NIH trial are related. A few studies in rats raised questions regarding potential effects on postnatal development, but in the absence of better study designs, the relevancy of these findings to human risk are also questionable at best.

CONCLUSION

There is a signal for embryo-fetal toxicity associated with 17-OHP-C in the two largest clinical trials conducted to date; there is also a signal for embryo-fetal toxicity with 17-OHP-C in rhesus monkeys and possibly one in rodent species. The relationship between these signals is unclear given the absence of state-of-the-art reproductive toxicology studies and human pharmacokinetic studies.

Getting to the heart of the matter: epidemiology of cyanotic heart defects

Congenital heart defects (CHDs) are the most common type of birth defect, making significant contributions to infant morbidity and mortality, but not all CHDs contribute equally to such outcomes. Although cyanotic CHDs constitute some of the most serious CHDs, its epidemiology is poorly understood. We present a comprehensive systematic review of the literature on the epidemiology of cyanotic CHD, with emphasis on the most current knowledge on identified risk/etiologic factors. Literature for this review was identified by searching the PubMed database from the National Center for Biotechnology Information at the US National Library of Medicine as well as bibliographies of identified papers. The 100 reports that contributed to this review describe risk factors such as infant sex, race, and ethnicity, environmental exposures, and maternal and paternal age. Several studies reported differences in prevalence rates by race and ethnicity and elevated sex ratios, and they identified some risk factors, including advanced maternal age. Investigators have made significant progress in the effort to describe the etiology of cyanotic CHDs, but discrepancies, such as the variation in prevalence rates by race and ethnicity and the impact of environmental exposures, still need to be addressed.

Noninherited risk factors and congenital cardiovascular defects: current knowledge: a scientific statement from the American Heart Association Council on Cardiovascular Disease in the Young: endorsed by the American Academy of Pediatrics

Prevention of congenital cardiovascular defects has been hampered by a lack of information about modifiable risk factors for abnormalities in cardiac development. Over the past decade, there have been major breakthroughs in the understanding of inherited causes of congenital heart disease, including the identification of specific genetic abnormalities for some types of malformations. Although relatively less information has been available on noninherited modifiable factors that may have an adverse effect on the fetal heart, there is a growing body of epidemiological literature on this topic. This statement summarizes the currently available literature on potential fetal exposures that might alter risk for cardiovascular defects. Information is summarized for periconceptional multivitamin or folic acid intake, which may reduce the risk of cardiac disease in the fetus, and for additional types of potential exposures that may increase the risk, including maternal illnesses, maternal therapeutic and nontherapeutic drug exposures, environmental exposures, and paternal exposures. Information is highlighted regarding definitive risk factors such as maternal rubella; phenylketonuria; pregestational diabetes; exposure to thalidomide, vitamin A cogeners, or retinoids; and indomethacin tocolysis. Caveats regarding interpretation of possible exposure-outcome relationships from case-control studies are given because this type of study has provided most of the available information. Guidelines for prospective parents that could reduce the likelihood that their child will have a major cardiac malformation are given. Issues related to pregnancy monitoring are discussed. Knowledge gaps and future sources of new information on risk factors are described.

Evaluating emerging issues in epidemiology

Industry and government institutions need a credible approach for evaluating and responding to emerging public health issues. Representatives of industry, government, and academia met under the auspices of the International Life Sciences Institute's Health and Environmental Sciences Institute (HESI) to develop successful strategies for dealing with emerging issues based on historical case studies. The case studies chosen for evaluation were (1) tampon use and toxic shock syndrome; (2) hazardous waste and childhood cancer risk in Toms River, New Jersey; (3) fenfluramine and phentermine use and valvular heart disease; (4) silicone breast implants and cancer and auto-immune disease; and (5) progestational drugs and birth defects. We identified eight lessons from these case studies. Foremost, we recommend that public and private institutions not defer action until an issue is scientifically resolved and stress that cooperation among issue stakeholders is critical for effective issue resolution. We suggest establishing a research program as an effective way to assure that good science is included in resolution of the issue. We further recommend frequent and timely communication with all stakeholders, and the development of research approaches to fill gaps when the scientific data on an issue are limited.

Population-based case-control teratogenic study of hydroxyprogesterone treatment during pregnancy

Hydroxyprogesterone, a synthetic progestin, was used for the treatment of pregnant women with threatened abortion and preterm delivery. Previous studies showed some association between hydroxyprogesterone use during early pregnancy and some specific congenital abnormalities. The population-based large Hungarian data set seemed to be appropriate to check this possible association. The Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996 includes 22 843 cases with congenital abnormalities and 38 151 controls without any defect. 318 (1.4%) cases, while 433 (1.1%) controls had mothers with hydroxyprogesterone treatment during pregnancy (adjusted POR with 95% CI: 1.3, 1.1-1.5). However, there was no association between risk for any congenital abnormality group and a higher use of maternal hydroxyprogesterone treatment during the second and third month of gestation. On the other hand hydroxyprogesterone is not effective in the prevention of preterm delivery. In conclusion, there was no detectable risk for congenital abnormalities in the offspring of mothers with hydroxyprogesterone treatment during early pregnancy, however, there is no reasonable indication of this treatment during pregnancy.

Nongenital malformations following exposure to progestational drugs: The last chapter of an erroneous allegation

In the late 1960s and 1970s, a number of epidemiological studies were published indicating that pregnant women who were exposed to an array of sex steroids delivered infants with an increased incidence of nongenital congenital malformations. Because of these publications, the Food and Drug Administration (FDA), in conjunction with various pharmaceutical companies, labeled the therapeutic exposure of progestational drugs and contraceptives in pregnant women as a risk factor for limb-reduction defects (LRDs) and congenital heart defects (CHDs). Subsequently there was a rapid decrease in the exposure of pregnant women to these drugs and the initiation of numerous lawsuits alleging that a particular progestational drug was responsible for a child's nongenital congenital malformation. Wilson and Brent (1981) published an article indicating that epidemiological and animal studies of these drugs, and basic science did not support the package insert's warnings. Many new and previous animal and epidemiological studies did not support the FDA box warning. In 1987 the FDA held a hearing in which the FDA, the Teratology Society, the Centers for Disease Control and Prevention, the American College of Obstetrics and Gynecology, and other organizations supported the position that progestational agents did not result in nongenital malformations. An editorial appeared in Teratology congratulating the FDA for removing the warning label on oral contraceptives regarding nongenital malformations. In 1999 the FDA published new wording for package inserts that removed warnings for nongenital malformations for all progestational agents. In spite of the recent changes in the package inserts, lawsuits have alleged that progestational drugs cause nongenital malformations. It took 22 years from the time a box warning was required by the FDA until the warnings were removed in 1999. The 1999 FDA publication, which is a scholarly and objective document, should put an end to 2 decades of concern and anxiety for pregnant women or women of reproductive age. Could scientists, the pharmaceutical companies, or the FDA have prevented the mislabeling of progestational drugs with regard to their teratogenic risks? Was the epidemiological or teratology community at fault because they did not critique and respond to the early publications? Did the FDA act too slowly? The epidemiologic analyses, animal studies, and basic science principles have been reviewed, and it is obvious that clinically utilized progestational drugs do not cause nongenital malformations (i.e., LRDs and CHDs).

Methodological issues in the epidemiological study of the teratogenicity of drugs

The review presented here discusses and exemplifies problems in epidemiological studies of drug teratogenesis according to methodology: case-control studies, cohort studies, or total population studies. Sources of errors and the possibility of confounding are underlined. The review stresses the caution with which conclusions have to be drawn when exposure data are retrospective or other possible bias exists. It also stresses the problem with the multiple testing situation that is usually present in the studies. It is therefore difficult to draw any firm conclusion from single studies and still more difficult to draw conclusions on causality. As randomized studies are in most cases out of the question, one has to rely on the type of studies which can be made, but the interpretation of the results should be cautious. The ideal study, next to a randomized one, is a large prospective study with detailed exposure information and detailed and unbiased outcome data. Even so, such a study can mainly be used for identifying possible associations which have to be verified or rejected in new studies. Nearly every finding of a risk increase, if not extremely strong, should only be regarded as a tentative signal to be tested in independent studies.

Risk factors for congenital heart diseases in Alexandria, Egypt

A matched case control study has been conducted in the children's hospitals in Alexandria, Egypt, during 2 years-period, aiming at investigating the risk factors for the occurrence of congenital heart diseases. Our results showed that the significant risk factors for developing any type of congenital heart disease and ventricular septal defects were: older paternal age at birth, positive consanguinity, positive family history, female sex hormones, irradiation, hazardous maternal occupation, diabetes mellitus and suburban or rural residence. However, some environmental/teratogenic factors were not implicated in the etiology of atrial septal defects or pulmonary stenosis. These findings strongly suggest that environmental factors vary according to the specific type of congenital heart disease. This study emphasizes on the need to instruct the public about the importance of pre-marital counseling and the deleterious effects of various teratogens in the environment.

Bob was right

During his career Bob Brent has been instrumental in developing the methodology to use in determining whether an exposure in pregnancy has a harmful effect on the fetus. Experience has also shown the importance of using this approach to determine when an exposure is not teratogenic. Unfortunately, the attendant debate, as illustrated in two examples reviewed, exogenous sex hormones and Bendectin, requires persistence and a thick skin. Bob has recorded in several publications how he carried out these systematic analyses. This literature will be a very valuable legacy.

Oral contraceptive side effects: where's the beef?

The initial report is reviewed, as well as the results of subsequent investigations, and the current status of the following side effects attributed to the use of oral contraceptives: subjective symptoms such as mood and libido changes, also headache; melanoma; gallbladder disease; liver tumors, sickle cell disease exacerbation; teratogenesis; "post-Pill" amenorrhea; atherogenesis; and diminished carbohydrate tolerance. In many instances a cause-and-effect relationship appears to be incorrect or highly improbable. In other instances the side effects are clinically insignificant or so rare as to be of minimal importance. Yet they continue to be listed by various authorities as validated side effects or relative contraindications to oral contraceptive use. This, in turn, limits the access of many women to a highly effective form of contraception. This re-examination of past history is intended to modernize our concepts of the safety of this modality.

Cardiovascular birth defects and prenatal exposure to female sex hormones: a reevaluation of data reanalysis from a large prospective study

In data of the U.S. Collaborative Perinatal Study (CPS), the Drug Epidemiology Unit (DEU) reported a relative risk of about 2.3 between maternal female sex hormone exposure during months 1 to 4 of pregnancy and cardiovascular malformation in infants (Heinonen et al., '77a N. Engl. J. Med., 296:67-70). Wiseman and Dodds-Smith ('84, Teratology, 30:359-370) reexamined the original CPS data and found the DEU had made some errors in classification of exposure and disease. Also they challenged the classification of cases as "exposed" in those born to mothers who received the compounds outside the day 19 to 50 window of cardiovascular embryogenesis. Wiseman and Dodds-Smith stated that their reanalysis "clearly showed that there was [in the data used by the DEU] no statistically significant association between exposure in the critical organogenic period of pregnancy and cardiac malformation in offspring." They did not undertake any statistical analysis, but their reanalysis resulted in a wide-spread nonacceptance of the association reported by the DEU. The study reported here reclassified the cases of the original DEU study in accord with the implications of the Wiseman and Dodds-Smith reanalysis of exposure and disease. After this reclassification, an effect magnitude measure of association, the relative risk rose from 2.33 to 2.48 and remained nominally significant statistically at the .05 level. Thus, if anything, the quantitative consequences of the Wiseman and Dodds-Smith review of the data, when applied in an unbiased manner, result in an increase in the measure of effect.(ABSTRACT TRUNCATED AT 250 WORDS)

A case-control study of major congenital heart defects in Sweden--1981-1986

This paper reports the results of a case-control study of major congenital heart defects (CHD) in Sweden. During the period 1981-1986, 1,324 such cases were identified and 2,648 controls were selected. Some common maternal characteristics and exposures were studied using information from prospectively collected data. Possible associations with CHD were found for previous perinatal death, maternal diabetes, epilepsy, hydramnios and disproportion between fetus and pelvis. More specific associations were observed between previous spontaneous abortion, epilepsy, hydramnios and truncus anomalies and between diabetes and septal anomalies. However, no associations were found with involuntary childlessness, contraceptive use, or smoking.

Cardiovascular birth defects and prenatal exposure to female sex hormones: a reevaluation of data reanalysis from a large prospective study

In data of the U.S. Collaborative Prenatal Study (CPS), the Drug Epidemiology Unit (DEU) reported a relative risk of about 2.3 between maternal female sex hormone exposure during months 1 to 4 of pregnancy and cardiovascular malformation in infants (Heinonen et al., '77a N. Engl. J. Med., 296:67-70). Wiseman and Dodds-Smith ('84) reexamined the original CPS data and found the DEU had made errors in classification of exposure and disease of some cases. Also they challenged the classification of cases as "exposed" in those born to mothers who received the compounds outside the day 19 to 50 window of cardiovascular embryogenesis. Wiseman and Dodds-Smith stated that their reanalysis "clearly showed that there was [in the data used by the DEU] no statistically significant association between exposure in the critical organogenic period of pregnancy and cardiac malformation in offspring." They did not undertake any statistical analysis, but their reanalysis resulted in a widespread nonacceptance of the association reported by the DEU. The study reported here reclassified the cases of the original DEU study in accord with the implications of the Wiseman and Dodds-Smith reanalysis of exposure and disease. After this reclassification, an effect magnitude measure of association, the relative risk rose from 2.33 to 2.48 and remained nominally significant statistically at the .05 level. Thus, if anything, the quantitative consequences of the Wiseman and Dodds-Smith review of the data, when applied in an unbiased manner, result in an increase in the measure of effect.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of dysmorphology in birth defects epidemiology

Most human teratogens have been identified by the clinical recognition of characteristic patterns of congenital anomalies among children whose mothers were exposed to a particular agent during pregnancy. Although this dysmorphologic method has been valuable, it is criticized because it is not easily amenable to statistical evaluation. Conventional birth defects epidemiological studies are designed to permit rigorous statistical assessment, but such investigations usually classify congenital anomalies without adequate consideration of their known etiological heterogeneity. It is possible to combine the best aspects of these two approaches to identifying human teratogens in a "dysmorphologic case/control study." Instead of including all available cases with a given defect, only individuals having the anomaly in the context of a multiple congenital anomaly pattern without a recognizable cause would be selected for inclusion among the case group. The frequency of exposure to the putative teratogen would be determined among these selected cases and among appropriately chosen controls; conventional statistical analysis would then be performed. Although this design reduces the size of the case group compared to a conventional case/control study, the statistical power is unchanged or increased. In addition, biological plausibility is increased by concentrating upon a group of cases that is more likely to have a teratogenic cause.

Placental production of estradiol and progesterone after oocyte donation in patients with primary ovarian failure

After oocyte donation 18 pregnancies were established in 17 patients with the absence of ovaries. Eight patients were delivered of nine healthy infants including one set of twins, six pregnancies were progressing normally, and four pregnancies were aborted. Four pregnancies were established after transfer of frozen-thawed embryos. In the simulated luteal phases, replaced with estradiol valerate and progesterone, pregnancies could be established and maintained as indicated by the profile of serum human chorionic gonadotropin concentrations. Weekly determinations of serum 17 beta-estradiol levels indicated significantly higher values at 7 weeks' gestation, as compared with week 5. This observation precludes that the luteoplacental shift occurred before 7 weeks' gestation. The weekly serum determinations of progesterone were significantly higher week 9, as compared with week 5. Two pregnancies were achieved after the vaginal administration of micronized progesterone.

Embryotoxicity of sex steroidal hormones in nonhuman primates: II. Hydroxyprogesterone caproate, estradiol valerate

Two sex steroid compounds which have been used clinically for parenteral supportive therapy of pregnancy were examined for embryotoxic effects in rhesus and cynomolgus macaques. Hydroxyprogesterone caproate (HPC) alone or in combination with estradiol valerate (EV) were administered intramuscularly (i.m.) to pregnant monkeys at 7-day intervals between 20 and 146 days of gestation and fetuses were examined following cesarean section at 150 +/- 2 days. HPC alone was tested in both species at doses ranging from 0.01 X to 10 X the human dose equivalent (HDE); only rhesus monkeys were exposed to the HPC + EV combination at 0.1 X to 10 X HDE. Total embryolethality resulted following the administration of HPC alone and combined with EV at 1 X and 10 X HDE in rhesus monkeys; the level of abortions in cynomolgus monkeys exposed to HPC (0.1 X to 1 X HDE) was comparable to controls. A small number of nonspecific malformations and developmental variations observed in cynomolgus fetuses after HPC exposure were considered to be incidental findings. No anomalies were found in surviving rhesus monkey fetuses treated with HPC + EV. The results indicate that long-term in utero exposure to the progestin, HPC, alone or in combination with EV in rhesus and cynomolgus monkeys, is embryolethal but not teratogenic at doses up to ten times the human therapeutic dose.

Embryotoxicity of sex steroidal hormone combinations in nonhuman primates: I. Norethisterone acetate + ethinylestradiol and progesterone + estradiol benzoate (Macaca mulatta, Macaca fascicularis, and Papio cynocephalus)

Two sex steroid hormone combinations which have been used clinically as tests for detection of early pregnancy were examined for embryotoxic effects in macaques and baboons. Norethisterone acetate and ethinyl estradiol (NEA + EE) were orally administered to rhesus and cynomolgus monkeys and baboons at dosages ranging from one to 1,000 times the human dose equivalent (HDE) during days 20-50 of pregnancy. Progesterone and estradiol benzoate (P + EB) were delivered by two to six intramuscular injections to rhesus and cynomolgus monkeys between gestational days 20 and 35 at 0.1-25 X HDE. Fetuses were examined following cesarean section at 100 +/- 2 days (NEA + EE) or at term (P + EB). The results showed increased embryolethality over controls at 100-1,000 X HDE (NEA + EE) and at 10 and 25 X HDE (P + EB). Besides growth retardation, isolated cases of minor nongenital malformations were observed only in cynomolgus monkeys following treatment with both hormone combinations mainly at embryolethal dose levels and were considered spontaneous in nature. Virilization of female cynomolgus fetuses following NEA + EE treatment was manifested as two cases of clitoral enlargement in the 300 X HDE group and two cases of increased anogenital distance with reduced vaginal opening in the 1,000 X HDE group. The highest dose of NEA + EE was also maternally toxic, as two maternal deaths occurred at the end of the treatment period. One dead female cynomolgus fetus exposed to P + EB (10 X HDE) also exhibited masculinized external genitalia.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryotoxicity of a single dose of medroxyprogesterone acetate (MPA) and maternal serum MPA concentrations in cynomolgus monkey (Macaca fascicularis)

A single dose of MPA (Depo-Provera; Upjohn Co., Kalamazoo, Michigan) was administered intramuscularly to 12 time-mated pregnant cynomolgus monkeys on day 27 (+/- 2) of gestation at 25 mg/kg or at 100 mg/kg. Maternal blood samples were collected immediately prior to MPA injection and then at regular intervals until cesarean section at term (day 152 +/- 3). Infants in both dose groups had external genital abnormalities. Female infants in the low-dose groups had partial or complete labial fusion, prominent median raphe, and clitoral hypertrophy; at high doses (100 mg/kg), the female infants had complete labial fusion and a distinct penile urethra. MPA had an opposite effect on external genitalia of male infants. The penis was short and the scrotal swelling was absent or less conspicuous, and two males had hypospadias. The adrenal glands were significantly smaller (P less than 0.05) in infants of both sexes treated with 100 mg/kg. One of the infants treated with 25 mg/kg of MPA had a muscular ventricular septal defect. Serum concentrations of MPA were determined by radioimmunoassay in eight pregnant monkeys. In the 25 mg/kg group the patterns of MPA profiles in the serum were similar in all four animals. An initial peak occurred at 24-48 hr postinjection (2.7-9.6 ng/ml), followed by a slight decrease at 3 days postinjection (gestational day 30), and then a steady increase to maximum levels of 10-14 ng/ml occurring between gestational days 37 and 50. Serum levels gradually declined to concentrations below 5 ng/ml by midgestation in three of four monkeys. By comparison, both the patterns and magnitude of MPA concentration showed great interanimal variation in the 100 mg/kg group. MPA was present in cord blood at measurable concentrations in infants at both dose groups; the levels ranged from 0.6 to 8.3 ng/ml, corresponding to 40-72% of the maternal concentrations. These results demonstrate that a single injection of MPA during early pregnancy causes selective embryotoxicity in both male and female fetuses. Presence of high levels of MPA in maternal sera during the critical period of genital development can cause specific genital defects; however, the exact mechanism by which MPA causes these paradoxical genital abnormalities is unknown.