Umbilical artery lactate levels and associated maternal and newborn characteristics at Mulago National Referral Hospital: A cross-sectional observational study

Objective: To determine the maternal and newborn characteristics associated with high umbilical artery lactate levels at Mulago National Referral Hospital.

Design: Cross-sectional observational study.

Setting: Department of Obstetrics and Gynecology at a national referral hospital located in the capital of Uganda, Kampala.

Participants: We randomly selected 720 pregnant mothers at term who presented in labour and their newborn babies.

Primary outcome: Umbilical artery lactate level.

Results: During the study, there were 579 vaginal deliveries (18 instrumental) and 141 caesarean sections which met the inclusion criteria. One hundred eighty seven neonates (187) had high arterial lactate levels. The following factors were associated with an increased likelihood of high lactate concentration: male sex (aOR = 1.71; 95%CI 1.16–2.54; P<0.05), primigravidity (aOR = 2.78; 95%CI 1.89-4.08; P < 0.001), Meconium stained liquor (MSL) (aOR = 5.85; 95%CI 4.08-8.47; P<0.001) and, Administration of oxytocin (aOR = 1.97; 95%CI 1.00-3.77; P<0.05).

Conclusion: About a fifth of the babies born in Mulago national referral hospital during the study period had high umbilical artery lactate. The maternal-fetal factors significantly associated with high umbilical artery lactate levels included: baby’s sex, mother’s gravidity, meconium stained amniotic fluid, and oxytocin administration during labour.

Methods
The participants’ baseline characteristics such as age, gravidity, gestational age, and blood pressure were collected using a data form.

Following vaginal or caesarean delivery, a 20 cm segment of umbilical cord was doubly clamped and one sample of 2 ml of arterial blood drawn from between the clamps within 5 minutes of delivery.

The first study assistant immediately used 20-30 µL of sampled blood and measured its lactate concentration using a point-of-care lactate meter (Accutrend Plus system; Roche Diagnostics, Rotkreuz Switzerland). The precision range of the meter is 0.8-22 mmol/L at 15 – 35oC and the coefficient of variation is 1.8 to 3%.

The newborn characteristic such as mode of delivery, sex, birth weight, and exposure to meconium stained amniotic fluid were also documented. We documented the Apgar score at 1 and 5 minutes, if the neonate was resuscitated after birth, admitted to the nursery, and if they died. It was also documented if the mother received any medication during the intrapartum period such as oxytocin, antibiotics, anti-convulsants (magnesium sulfate), and prostaglandins for labour induction.