If Your Baby Was Small at Birth

Many babies with neonatal diabetes are born small — often noticeably smaller than expected for the length of the pregnancy. If that was true of your baby, it is not a coincidence and it is not a sign that something went wrong during the pregnancy.

Insulin is one of the main growth signals before birth. A baby who cannot make enough insulin in the womb grows less. In one series of infants with the transient form, average birth weight was around 1,930 g at a full 39 weeks — well below what would normally be expected. In a South Indian group of babies with permanent neonatal diabetes, the median birth weight was about 2,345 g.

Doctors call this being small for gestational age, or intrauterine growth restriction. In this context it is a clue rather than a complication, and it is one of the features that points towards a genetic cause.

The encouraging part is what usually happens next. Once insulin is supplied, the growth signal is restored, and most babies grow well from there. In that South Indian group, children followed over several years moved up the growth charts, with weight rising from around the 2nd to the 13th percentile and height from roughly the 6th to the 20th.

Catch-up takes time and it is measured in months, not weeks. Your paediatrician will plot weight, length and head circumference at every visit, and that chart becomes one of the clearest signs that treatment is working.

This is covered further in tracking growth on the charts.