Sex differences in regional specialisation across the placental surface

Area of Science:

• Obstetrics and Gynecology
• Human Anatomy
• Perinatal Medicine

Background:

• Regional specialization in placental structure and function is suggested.
• Previous studies in Riyadh indicated correlations between placental dimensions and infant size, with breadth being more influential.

Purpose of the Study:

• To investigate placental surface specialization in Baish, Saudi Arabia, and compare findings with Riyadh.
• To examine sex-specific associations between placental dimensions and newborn anthropometrics.

Main Methods:

• A study involving 321 pregnant Saudi women in Baish.
• Measurement of newborn anthropometrics (birth weight, crown-heel length, head and thigh circumferences) and placental dimensions (length and breadth).

Main Results:

• Placental surface dimensions showed sex-specific associations with infant body size in Baish.
• In boys, placental breadth correlated strongly with most birth measurements, similar to Riyadh findings.
• In girls, placental breadth related to crown-heel length, while surface length correlated with birth weight and circumferences.

Conclusions:

• Geographical and sex-based differences in placental regional specialization exist within Saudi Arabia.
• Adverse conditions in Baish, potentially linked to maternal stature, resulted in smaller birth sizes for boys compared to girls.
• Boys may have compensated for under-nutrition via deeper spiral artery invasion, while girls exhibited more effective placental specialization.