[Analysis of physical growth of preterm infants with different intrauterine growth patterns in Haikou]

Abstract

Objective: To analyze the physical growth of preterm infants with different intrauterine growth patterns. Methods: A total of 10 856 preterm infants who were born in various districts of Haikou City from October 1st, 2015 to June 1st, 2021 and received regular health care and management were retrospectively enrolled. The preterm infants were divided into appropriate for gestational age (AGA), small for gestational age (SGA) and large for gestational age (LGA) groups according to different intrauterine growth patterns. The general characteristics of preterm infants in different groups were compared by H test (Kruskal and Wallis) or Chi-squared test. And the developmental curves were plotted by local regression (LOESS) with their physical growth indexes. Results: Of the 10 856 preterm infants, 6 317 were boys and 4 539 were girls. The gestational age at birth was 35 (34, 36) weeks, and the birth weight was 2.5 (2.1, 2.8) kg. There were 754 (6.9%) SGA, 9 301 (85.7%) AGA, and 801 (7.4%) LGA preterm infants. All preterm infants were followed up until 18 months of corrected age. The birth weight of the SGA group was lower than that of the AGA and LGA groups (Z=2 274.93, P<0.001). The proportion of exclusive breastfeeding at the first health care interview was higher in the AGA group (68.6% (6 378/9 301)) than in the SGA group (62.9% (474/754)) (χ²=13.82, P=0.003). The LOESS curving fitting showed that the weight and height of the preterm infants in all the 3 groups increased rapidly during 0-6 months of corrected age. The regression prediction values of weight for age Z-score (WAZ), height for age Z-score (HAZ) and weight for height Z-score (WHZ) were around 0 s, while the regression prediction values of these three indicators in SGA were all below 0 s but greater than -1 s. The rates of low birth weight, growth retardation and wasting during 0-17 months of corrected age were 0.3% (16/4 838)-1.9% (47/2 506), 0.4% (18/4 838) -2.4% (51/2 124), and 2.1% (88/4 135) -4.4% (214/4 838) in AGA groups, and 0 (0/296) -1.0% (2/199), 0 (0/341) -1.6% (3/186) and 1.0% (2/199) -2.6% (9/341) in LGA group, whereas 7.6% (25/330) -16.8% (28/167), 5.2% (17/330)-10.6%(32/303) and 3.9% (3/77) -12.6% (21/167) in SGA group. In addition, the monthly growth of weight and height of preterm infants in all the 3 groups decreased with the increasing age, and the monthly weight gain. The length increment was 4.0 cm/month during corrected 0-2 month of age and 2.4 cm/month during corrected 2-5 month of age in the SGA preterm infants. Conclusions: Most of the preterm infants could have an appropriate catch-up growth, but the growth and development in the SGA preterm infants lags behind that of their AGA and LGA peers. The physical growth of SGA premature infants should be paid more attention to, to timely correct the growth deviations.