Pregnancy Outcome Among Twins Conceived After Subfertility Treatment Compared With Natural Twins: A Population-Based Study

Therapeutic Approaches for Zika Virus Infection of the Nervous System

Zika virus has spread rapidly in the Americas and has caused devastation of human populations affected in these regions. The virus causes teratogenic effects involving the nervous system, and in adults and children can cause a neuropathy similar to Guillain-Barré syndrome, an anterior myelitis, or, rarely, an encephalitis. While major efforts have been undertaken to control mosquito populations that spread the virus and to develop a vaccine, drug development that directly targets the virus in an infected individual to prevent or treat the neurological manifestations is necessary. Rational and targeted drug development is possible since the viral life cycle and the structure of the key viral proteins are now well understood. While several groups have identified therapeutic candidates, their approaches differ in the types of screening processes and viral assays used. Animal studies are available for only a few compounds. Here we provide an exhaustive review and compare each of the classes of drugs discovered, the methods used for drug discovery, and their potential use in humans for the prevention or treatment of neurological complications of Zika virus infection.

Adverse pregnancy, birth, and infant outcomes in twins: effects of maternal fertility status and infant gender combinations; the Massachusetts Outcomes Study of Assisted Reproductive Technology

BACKGROUND

It is unknown whether the risk of adverse outcomes in twin pregnancies among subfertile women, conceived with and without in vitro fertilization, differs from those conceived spontaneously.

OBJECTIVE

We sought to evaluate the effects of fertility status on adverse perinatal outcomes in twin pregnancies on a population basis.

STUDY DESIGN

All twin live births of ≥22 weeks' gestation and ≥350 g birthweight to Massachusetts resident women in 2004 through 2010 were linked to hospital discharge records, vital records, and in vitro fertilization cycles. Women were categorized by their fertility status as in vitro fertilization, subfertile, or fertile, and by twin pair genders (all, like, unlike). Women whose births linked to in vitro fertilization cycles were classified as in vitro fertilization; those with indicators of subfertility but without in vitro fertilization treatment were classified as subfertile; all others were classified as fertile. Risks of 6 adverse pregnancy outcomes (gestational diabetes, pregnancy hypertension, uterine bleeding, placental complications [placenta abruptio, placenta previa, and vasa previa], prenatal hospitalizations, and primary cesarean) and 9 adverse infant outcomes (very low birthweight, low birthweight, small-for-gestation birthweight, large-for-gestation birthweight, very preterm [<32 weeks], preterm, birth defects, neonatal death, and infant death) were modeled by fertility status with the fertile group as reference, using multivariate log binomial regression and reported as adjusted relative risk ratios and 95% confidence intervals.

RESULTS

The study population included 10,352 women with twin pregnancies (6090 fertile, 724 subfertile, and 3538 in vitro fertilization). Among all twins, the risks for all 6 adverse pregnancy outcomes were significantly increased for the subfertile and in vitro fertilization groups, with highest risks for uterine bleeding (adjusted relative risk ratios, 1.92 and 2.58, respectively) and placental complications (adjusted relative risk ratios, 2.07 and 1.83, respectively). Among all twins, the risks for those born to subfertile women were significantly increased for very preterm birth and neonatal and infant death (adjusted relative risk ratios, 1.36, 1.89, and 1.87, respectively). Risks were significantly increased among in vitro fertilization twins for very preterm birth, preterm birth, and birth defects (adjusted relative risk ratios, 1.28, 1.07, and 1.26, respectively).

CONCLUSION

Risks of all maternal and most infant adverse outcomes were increased for subfertile and in vitro fertilization twins. Among all twins, the highest risks were for uterine bleeding and placental complications for the subfertile and in vitro fertilization groups, and neonatal and infant death in the subfertile group. These findings provide further evidence supporting single embryo transfer and more cautious use of ovulation induction.

Perinatal outcomes associated with assisted reproductive technology: the Massachusetts Outcomes Study of Assisted Reproductive Technologies (MOSART)

OBJECTIVE

To compare on a population basis the birth outcomes of women treated with assisted reproductive technologies (ART), women with indicators of subfertility but without ART, and fertile women.

DESIGN

Longitudinal cohort study.

SETTING

Not applicable.

PARTICIPANT(S)

A total of 334,628 births and fetal deaths to Massachusetts mothers giving birth in a Massachusetts hospital from July 1, 2004, to December 31, 2008, subdivided into three subgroups for comparison: ART 11,271, subfertile 6,609, and fertile 316,748.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Four outcomes-preterm birth, low birth weight, small for gestational age, and perinatal death-were modeled separately for singletons and twins with the use of logistic regression for the primary comparison between ART births and those to the newly created population-based subgroup of births to women with indicators of subfertility but no ART.

RESULT(S)

For singletons, the risks for both preterm birth and low birth weight were higher for the ART group (adjusted odds ratios [AORs] 1.23 and 1.26, respectively) compared with the subfertile group, and risks in both the ART and the subfertile groups were higher than those among the fertile births group. For twins, the risk of perinatal death was significantly lower among ART births than fertile (AOR 0.55) or subfertile (AOR 0.15) births.

CONCLUSION(S)

The use of a population-based comparison group of subfertile births without ART demonstrated significantly higher rates of preterm birth and low birth weight in ART singleton births, but these differences are smaller than differences between ART and fertile births. Further refinement of the measurement of subfertile births and examination of the independent risks of subfertile births is warranted.

Outcomes of IVF conceptions: are they different?

Perinatal outcomes, such as preterm delivery, low birth weight and some obstetric complications, are increased significantly after in-vitro fertilization (IVF) compared with spontaneously conceived pregnancies. The degree of difference is greater for singletons than for twins, especially with regard to preterm delivery which is increased two fold in IVF singletons and by 40% in twins. It is difficult to obtain accurate outcome information because of unmeasured confounders such as smoking status and fetal reduction. It is also unknown whether IVF technologies or patient infertility is the major contributor to adverse outcomes. Birth defects are increased, shown in a number of systematic reviews, and there has been a particular interest in imprinting syndromes. Epigenetic modifications may play a larger role in IVF outcomes, as yet unidentified. There is no apparent increase in adverse outcomes in children up to adolescence, although further studies are needed to examine longer-term risks, including those for cancer.