[Maternal factors influencing breastfeeding on a neonatal intensive care unit]

Admission at birth to a Neonatal Intensive Care Unit (NICU) complicates breastfeeding especially for preterm babies despite hospital staff trained to encourage breastfeeding. The aim of this study was to find factors related to the mother, the pregnancy or the neonate influencing breastfeeding rate on a NICU.

This was a retrospective study including neonatal admissions to the NICU at Antoine-Béclère University Hospital from 1st May 2009 to 30th April 2010. Data was collected from medical notes. The breastfeeding rate (at initiation and at discharge) was analysed with regards to maternal age, method of procreation, type of pregnancy (single or multiple), parity, mode of delivery (vaginal delivery or C-section), birthweight, gestational age and intra-uterine growth restriction (IUGR).

The study was based on 460 neonates having complete documentation. The average maternal age was 32 years. Premature infants represented 74.8% of the population (median gestational age=34 weeks) of which 57% were less than 33 weeks (42.6% of all infants, n=196). The median birthweight was 1900 g with 17.6% of IUGR infants. Breastfeeding rate at initiation was 58.7 and 43.9% at discharge (mean admission days: 17.1 [0-180], median=8 days). For infants born of multiple pregnancies (24.3% of the population) 51.6% were born of medically assisted pregnancies (MAP) and 17.6% of spontaneous pregnancies. Breastfeeding rate among these infants was 57.1% at initiation and 45.5% at discharge. It was higher in infants born of MAP at initiation (70.3% versus 55.8% for spontaneous pregnancies, P<0.05) and at discharge (49.5% versus 42.5% for spontaneous pregnancies). For these infants, average maternal age was higher for breastfed infants (33.9 versus 32.1 years for the formula-fed, P<0.05). Breastfeeding rate in infants born to primipares was higher at initiation (64.9% versus 53.6% for multipares, P<0.05) and at discharge (48.5% versus 40.8% for multipares, P<0.05). The rate of infants breastfed was influenced neither by maternal age alone (31.8 ± 5.6 versus 31.4 ± 5.7 years for formula-fed), nor by type of delivery (56.7% for infants born by C-section versus 62.5% for infants born by vaginal delivery), nor gestational age (33.2 ± 4.3 weeks for breastfed, versus 33.4 ± 4.2 weeks for formula-fed infants), nor birthweight (2060 ± 978 g for breastfed versus 2055 ± 909 g for formula-fed infants), nor IUGR (58% versus 58.8% for eutrophes).

Our maternal population was different as 16.7% of deliveries were accounted for by MAP, superior to the French average (<10%). We describe for the first time MAP as a positive influencing factor on breastfeeding rates in newborns admitted to a NICU. A better breastfeeding information policy during pregnancy, higher maternal age and increased multiple pregnancies would explain a higher breastfeeding rate among the women who had MAP. An impact of increasing maternal age was found on the rate of breastfed infants born of MAP. Primiparity was also a contributing factor for breastfeeding. Professional formation for all hospital staff concerned would be essential to give out clear and consistent information to families and to encourage support and intimacy throughout hospitalisation as well as at discharge.