Maternal Serum Progesterone and BMI and Neonatal Sex Ratios After Single FET

09 Apr 20264 min read0 viewsJournal Feed

GIST

This retrospective cohort study examined whether maternal serum progesterone (PRG) and body mass index (BMI) measured in the peri-transfer period are associated with neonatal sex after single blastocyst frozen–thawed embryo transfer (FET) under a freeze-all strategy. The analysis included 998 cycles performed from 2019 to 2023.

Receiver operating characteristic (ROC) analyses identified candidate thresholds: PRG ≤ 21.11 ng/mL and BMI ≤ 21.30 kg/m² as predictive for male birth. In multivariable logistic regression models adjusted for potential confounders, low PRG was associated with higher odds of a male offspring (odds ratio [OR] 1.61; 95% confidence interval [CI] 1.09–2.36; P = 0.016).

Low BMI was also linked with increased odds of male birth (OR 2.33; 95% CI 1.61–3.40; P value not provided in excerpt). The authors report that maternal PRG levels and BMI together correlate with neonatal sex ratios after FET, suggesting endocrine and metabolic environments may influence embryo–endometrium interactions in a sex-specific manner.

The study acknowledges that causality cannot be established and presents hypothesis-generating findings; uncertainty remains regarding underlying mechanisms and generalizability.

Clinical Editorial

Context and objective

The study examines whether maternal serum progesterone (PRG) and body mass index (BMI) relate to neonatal sex following single frozen–thawed embryo transfer (FET) within a freeze-all framework.

Design and population

Retrospective cohort study including 998 single blastocyst FET cycles conducted from 2019 to 2023.
Peri-transfer maternal measurements included BMI and serum PRG.

Methods and analyses

Receiver operating characteristic (ROC) analyses were used to identify predictive thresholds for neonatal sex outcomes.
Associations between PRG, BMI, and neonatal sex were assessed with multivariable logistic regression models that adjusted for potential confounders.

Key findings

ROC-derived cut-offs for predicting male birth were PRG ≤ 21.11 ng/mL and BMI ≤ 21.30 kg/m².
Lower PRG was associated with higher odds of male offspring (odds ratio [OR] 1.61; 95% CI 1.09–2.36; p = 0.016).
Lower BMI was associated with higher odds of male offspring (OR 2.33; 95% CI 1.61–3.40).

Context and interpretation

The combination of maternal endocrine and metabolic factors appears to correlate with neonatal sex ratios after FET.
The authors describe the findings as hypothesis-generating, noting that the study does not establish causality.

Limitations and scope

The report emphasizes observational associations and does not claim causal relationships.
Specific limitations beyond the stated need for cautious interpretation are not detailed in the provided text.

Practical relevance and open questions

The results suggest avenues for further research into how endocrine and metabolic environments may influence embryo–endometrium interactions in a sex-specific manner.