Abstract

Oxytocin is a hormone involved with adjustment of pregnancy, the process of delivery, breastfeeding, social recognition and bonding. This study aimed at determining the serum levels of oxytocin in pregnancy, during labour, and in the puerperium for Nigerian females in Zaria. It was a cross-sectional study of one hundred and twenty women aged 18 to 45 years from four hospitals in Zaria. The women were grouped into four groups comprising non-pregnant women (control), pregnant women (first, second, and third trimester), women in labour and in their first week after delivery. Questionnaires were administered to the women and their blood samples collected via venipuncture between 09.00 and 13.00 h. After centrifuging the blood samples, the sera were analyzed with human oxytocin ELISA kits at the Department of Chemical Pathology, Ahmadu Bello University Teaching Hospital, Shika. Results were presented as frequencies, percentages and mean ± standard deviation (SD) while data was analyzed using one-way analysis of variance (ANOVA), Tukey post-hoc test and the reference range (defined as 95% confidence limits) was determined. A statistical significance of p<0.05 was selected. Serum oxytocin levels (non-pregnant controls: 82.80 ± 23.68 pg/ml; 95% Confidence Interval (CI): 73.02 to 92.58 pg/ml) rose progressively with advancing gestation (first trimester: 167.56 ± 24.17 pg/ml, 95% CI: 148.98 to 186.13 pg/ml; second trimester: 377± 53.113 pg/ml, 95% CI 358.50 to 396.17 pg/ml), but there were no significant differences in serum oxytocin concentration for women in their third trimester (499.06 ± 42.06 pg/ml; 95% CI: 483.64 to 514.49 pg/ml) as compared to women during labour (525.0 ± 35.98 pg/ml; 95% CI: 497.35 to 552.65 pg/ml) and the puerperium (spontaneous vaginal delivery: 532.25 ± 29.93 pg/ml; 95% CI: 507.23 – 557.27 pg/ml; caesarean section: 502.40 ± 42.34 pg/ml; 95% CI: 449.83 to 554.97 pg/ml), p>0.05. Maternal serum oxytocin levels at spontaneous vaginal delivery (532.25 ± 29.93 pg/ml; 95% CI: 507.23 to 557.27 pg/ml) were higher than those at caesarean section (502.40 ± 42.34 pg/ml; 95% CI: 449.83 to 554.97 pg/ml) though not statistically significant (p>0.05). In conclusion, it appears that maternal oxytocin levels in Nigerian females though following the pattern in other studies had higher values.

Key words: Enzyme immunoassay, lactation, pregnancy hormone, reference range, serum oxytocin, Zaria.