Understanding Pregnancy Loss, Fertility, and Contraception

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NICHD research projects continue to broaden knowledge about the spectrum of issues that affect family planning and help ensure healthy pregnancies.

With support from NICHD’s Human Placenta Project, researchers developed a potential same-day test to identify abnormal fetal chromosomes, a common cause of pregnancy loss. The investigators compared their Short-read Transpore Rapid Karyotyping (STORK) test with standard methods by evaluating more than 200 diverse tissue and fluid samples. Their results suggest that STORK can quickly and inexpensively detect extra or missing chromosomes with accuracy comparable to that of standard tests. Although larger studies are needed to validate STORK, it may be useful for providing rapid identification of genetic causes of miscarriage and in screening embryos produced by in vitro fertilization.

To advance understanding of fertility and infertility, one NICHD-funded study found that weight loss before infertility treatment does not improve the live birth rate among women with obesity and unexplained infertility. Researchers found no difference in the proportion of live births among women with obesity and unexplained infertility who lost weight before infertility treatment and a similar group who did not lose weight before treatment. The findings from this study of nearly 380 women suggest that there is insufficient evidence to recommend preconception weight loss prior to treatment of infertility in women with obesity and unexplained infertility.

Another study, conducted by NICHD scientists, found that children conceived through infertility treatment may have a higher risk for asthma and allergies. Compared to children conceived without infertility treatment, those conceived after treatment were more likely to have persistent wheeze by age 3, a potential indication of asthma. At 7 to 9 years old, children conceived with treatment were 30% more likely to have asthma, 77% more likely to have eczema, and 45% more likely to have a prescription for an allergy medication. Further research is needed to explore how infertility treatment or parental fertility may influence the development of asthma and allergy in children.

The institute also supports a broad portfolio of basic research and clinical studies on contraception. For example, NICHD-supported work identified potential nonhormonal male contraceptives that block the action of bromodomain testis-specific protein (BRDT), which comprises the two closely related domains, BD1 and BD2. Previous studies established that BRDT-BD1 is essential for fertility in mice and suggested that blocking BRDT-BD2 may cause undesirable side effects. Using a novel screening technique, the researchers evaluated more than 4.5 billion small-molecule compounds to identify several that potently inhibit BRDT-BD1 but do not affect BDRT-B2. Research efforts on this nonhormonal contraceptive target are ongoing.

Another contraceptive strategy used antibodies to cause sperm to clump together and become immobilized, a process called agglutination. These antibodies also have the potential to trap pathogens in mucus, a feature that NICHD-supported scientists described in a recent review article. Mucus trapping can prevent pathogens from infecting cells and accelerate their removal from the body. Developing ways to exploit this feature of antibodies holds promise for developing both topical contraceptives and multipurpose prevention technologies—products designed to prevent both pregnancy and sexually transmitted infections.

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