Pregnancy registries are valuable sources of information. For many drugs, they are the primary source of the human pregnancy experience. However, although most of the registries use the word “pregnancy,” it is important to note that many also enroll women who took the target drug shortly before conception.
The strengths of these registries are their prospective nature (enrolled before the outcome is known) and enrollment over a wide geographical area. Typically, two types of pregnancy outcomes are obtained: those with birth defects and those without known birth defects (classified as live births, fetal deaths, and spontaneous abortions). Registries can identify early signals of teratogenicity, but they have several limitations: selection bias that results from voluntary reporting; target populations that are not representative; lost-to-follow-up pregnancies that may have had different outcomes than those with documented outcomes; elective terminations and fetal deaths without birth defects and spontaneous abortions, all of which may lack details; the lack of control groups (with some exceptions); and the publication of results that may be delayed or not be in a peer-reviewed journal. Because the total number of exposed pregnancies is unknown, the data cannot be used to calculate prevalences, but they can be used to estimate the proportion of birth defects. Some registries also collect data on retrospective reports (reported after outcome is known). Such reports are less representative of the target population because they can be biased toward the reporting of more unusual and severe outcomes. But they may be helpful in detecting unusual patterns of birth defects.
For the following drugs, web addresses can be obtained from the Food and Drug Administration website,
A large registry, the MotherToBaby Organization of Teratology Information Specialists (OTIS) (877-311-8972), involves patients in several different categories and the effects of the drugs on the embryo-fetus: autoimmune diseases (ankylosing spondylitis, rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, psoriasis, Crohn’s disease, and multiple sclerosis); asthma at less than 20 weeks’ gestation; vaccines; and heterozygous or homozygous familial hypercholesterolemia.
For the autoimmune diseases, the drugs and trade names are abatacept (Orencia), adalimumab (Humira), certolizumab pegol (Cimzia), etanercept (Enbrel), infliximab (Remicade), leflunomide (Arava), otezla (Apremilast), teriflunomide (Aubagio), tocilizumab (Actemra), tofacitinib (Xeljanz), and ustekinumab (Stelara).
For the asthma group, the drug being investigated is mepolizumab (Nucala).
Two vaccines – for tetanus, diphtheria, and pertussis (Tdap) and meningococcal disease caused by Neisseria meningitidis serogroups A, C, Y and W-135 (Menveo) – are being studied.
The last category is heterozygous or homozygous familial hypercholesterolemia. The two agents in this category are alirocumab (Praluent) and evolocumab (Repatha).