Twins less frequent than expected among male births in risk averse populations.

Male twin gestations exhibit higher incidence of fetal morbidity and mortality than singleton gestations. From an evolutionary perspective, the relatively high rates of infant and child mortality among male twins born into threatening environments reduce the fitness of these gestations, making them more vulnerable to fetal loss. Women do not perceive choosing to spontaneously abort gestations although the outcome may result from estimates, made without awareness, of the risks of continuing a pregnancy. Here, we examine whether the non-conscious decisional biology of gestation can be linked to conscious risk aversion. We test this speculation by measuring the association between household surveys in Sweden that gauge financial risk aversion in the population and the frequency of twins among live male births. We used time-series regression methods to estimate our suspected associations and Box-Jenkins modeling to ensure that autocorrelation did not confound the estimation or reduce its efficiency. We found, consistent with theory, that financial risk aversion in the population correlates inversely with the odds of a twin among Swedish males born two months later. The odds of a twin among males fell by approximately 3.5% two months after unexpectedly great risk aversion in the population. This work implies that shocks that affect population risk aversion carry implications for fetal loss in vulnerable twin pregnancies.

Cost-effectiveness of cytogenetic evaluation of products of conception in the patient with a second pregnancy loss.

OBJECTIVE: To compare the cost of two strategies for managing the patient with recurrent pregnancy loss (RPL). DESIGN: Cost analysis using a decision analytic model was used to compare obtaining an evidence-based workup (EBW) for RPL versus obtaining a karyotype of the products of conception (POC) and proceeding with an EBW only in the setting of euploid POC. SETTING: Outpatient care. PATIENT(S): A simulated cohort of patients experiencing a second pregnancy loss. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Total cost of investigating the cause of RPL after a second pregnancy loss. RESULT(S): For all age categories, obtaining a karyotype of POC was less costly than an evidenced-based RPL evaluation. Monte Caro analysis demonstrated a net economic benefit for the karyotype strategy ($4,498 [±$792] vs. $5,022 [±$1,130]). CONCLUSION(S): Our model suggests an economic advantage for obtaining a karyotype of POC in women with second miscarriage.

Assessment of sperm factors possibly involved in early recurrent pregnancy loss.

OBJECTIVE: To evaluate and compare standard sperm parameters, lipid peroxidation of sperm plasma membranes, antioxidant capacity of seminal plasma, and sperm chromatin integrity in ejaculates from men whose partners have a history of recurrent pregnancy loss and from a control group of men with recent fertility. DESIGN: Descriptive study. SETTING: Reproduction Program, University of Antioquia, Medellín, Colombia. PATIENT(S): Twenty-three couples with history of recurrent pregnancy loss and 11 men with recent fertility. INTERVENTION(S): Semen samples from control men and men whose partner had a history of recurrent pregnancy loss were examined for differences in semen parameters, lipid peroxidation, antioxidant capacity, DNA fragmentation index, and sperm preparation. MAIN OUTCOME MEASURE(S): Migration-sedimentation method was used to collect motile spermatozoa from fresh ejaculates for examination for semen parameters. RESULT(S): Men from the control group had spermatozoa with higher percentage of normal sperm morphology, concentration, progressive motility, and antioxidant capacity compared with men from the recurrent pregnancy loss group, who had spermatozoa with higher teratozoospermia and higher lipid peroxidation. Motile sperm fractions from both groups had spermatozoa with better sperm parameters compared with freshly ejaculated sperm. CONCLUSION(S): This study strengthens the current literature associating sperm quality with recurrent pregnancy loss, and emphasizes the importance of evaluating male factor by tests such as lipid peroxidation and measuring antioxidant capacity of seminal plasma in addition to conventional sperm parameters.