A Consultant Obstetrician and Gynaecologist at the Nigerian Institute of Medical Research, Yaba, Lagos, Dr. Gregory Ohihoin, says sexual intercourse may help to initiate labour in pregnant women who have passed their estimated day of delivery.
Dr. Ohihoin said having sex at term helps to promote prostaglandins, which may help induce labour.
The prostaglandins are a unique group of pharmacologically active lipids that are widely distributed in mammalian tissues and body fluids.
Ohihoin spoke in reaction to a study published in the Iranian Red Crescent Medical Journal, showing that sexual activity in the last week of pregnancy might be associated with the onset of labour.
The cross-sectional study included 120 pregnant women with signs of labour onset at referral hospitals of Kashan University of Medical Sciences between November and March 2012.
Speaking with PUNCH HealthWise, Dr Ohihoin said prostaglandins are substances that help labour to progress when a woman is at term.
“If a woman is going through prolonged labour, one of the things that are used to initiate labour in a woman is prostaglandins.
“When a woman is near term for delivery and she has sexual intercourse, it promotes prostaglandins and it can help to initiate labour.
“When pregnancy is close to term, the uterus becomes very sensitive to prostaglandin. There is what is called the oxytocin receptor in the uterus, all of those things make the uterus very sensitive to prostaglandins and this does not occur when the pregnancy is not close to term.
“However, if a woman is having sexual intercourse when she is not close to term, it will not lead to labour. It is only when the woman is near term that there is high sensitivity of the uterus to prostaglandins.
“When the woman is having prolonged pregnancy, or when the pregnancy is overdelayed, sexual intercourse can help to initiate labour process,”
the physician said.
According to experts, oxytocin is a hormone that acts on organs in the body (including the breast and uterus) and as a chemical messenger in the brain, controlling key aspects of the reproductive system, including childbirth and lactation, and aspects of human behaviour.
Ohihoin added that it is not good for any pregnancy to go beyond 40 or 41 weeks, warning that complications can occur.
The signs of labour onset included labour pain, bloody show, or rupture of membrane and the subjects were investigated in two groups regarding the history of coitus in the last week of pregnancy.
In the Iranian study, a questionnaire containing demographic questions, obstetrical history, and sexual activity was completed by a trained midwife through a face-to-face interview. Chi-square test, Fisher’s exact test, and t-test were used to check the homogeneity of the two groups for basic and confounding variables.
The researchers also used independent-samples t-test to compare differences between groups in terms of mean gestational age.
The researchers led by Mahboobeh Kafaei Atrian said there was no significant difference between groups in age (P = 0.434), body mass index (P = 0.705), neonatal weight (P = 0.421), maternal education (P = 0.963), occupation (P = 0.381), and parity (P = 0.925).
“Gestational age at the time of delivery was significantly lower in intercourse group in comparison with control group based on last menstrual period (P = 0.012) and ultrasonography (P = 0.002). There was no correlation between intercourse and cause of admission (P = 0.720).
“Type of delivery (cesarean section or vaginal delivery) was not affected by intercourse (P = 0.820) or contact with semen (P = 0.841).
“Results showed no significant difference in neonatal weight based on presence of sexual intercourse (P = 0.422) or contact with semen (P = 0.583) at the last week of pregnancy,”
the researchers said.
They concluded that sexual activity in the last week of pregnancy might be associated with the onset of labour.
“Therefore, in the absence of complications in term pregnancy, sexual activity can be considered as a natural way to prevent post-term pregnancy,”