Exclusive breastfeeding is currently recommended until at least 6 months of postnatal age, due to maternal breast milk (BM) unique composition and beneficial properties. In fact, BM modifies itself according to gestational age (GA) at birth, adapting its composition to neonatal requests during lactation. Multiple births represent about 3% of the whole pregnancies; such neonates result more vulnerable than full-term newborns, due to lower GA and birth weight (BW) and the higher incidence of perinatal complications. Although an adequate nutrition is fundamental for twins and other multiples, studies on this topic are lacking. We collected and analyzed BM from mothers of 19 twins and 5 triplets showing GA < 33 weeks and BW < 1500 g, comparing it to a control group of 28 preterm singletons. As a result, at GA ≤ 28 weeks, we observed that protein content is higher in BM for multiples (1.53 vs. 1.29 g per 100 ml), lactose concentration is greater in BM for singletons (6.72 vs. 6.34 g per 100 ml) and GA results the most relevant factor influencing BM protein composition. BM for multiples results higher in proteins and lower in lactose, if compared with singleton’s samples; this could promote and sustain growth and organ development in this vulnerable category. BM from multiples shows a trophic and immunologic role, since these neonates often show lower GA and BW instead of singletons. These findings could help in optimizing nutritional strategies and improving BM individualized fortification.

Using vital statistics, yearly changes in the twinning and triplet rates by zygosity were investigated in the Czech Republic and the Slovak Republic during the period 1972–1995. Monozygotic (MZ) twinning rates in both countries had remained nearly constant (about 3 per 1000 total births) during that period. With a few exceptions, the dizygotic (DZ) twinning rates remained constant from 1972 to 1994, and increased in 1995 for both countries. MZ twinning rates for both countries were the lowest in Europe. As for triplet rates, overall rates increased significantly year by year in the Czech Republic, but not in the Slovak Republic. The triplet rate was significantly higher in 1995 than in the period 1972–1982 for both countries. The MZ triplet rate remained constant during that period in the Czech Republic. The trizygotic (TZ) triplet rates increased 3-fold for the Czech Republic and 4-fold for the Slovak Republic in 1972–1976 and 1992–1995. In the later period, the TZ rate was 1.5-fold higher in the Czech Republic than in the Slovak Republic. The quadruplet rate increased 2.3-fold from 2.9 per million births in 1982–1986 to 6.7 in 1992–1995 in the Czech Republic. The corresponding values were 2.7, 2.20 and 5.9-fold in the Slovak Republic. Both the Czech and the Slovak Republics were not affected by fertility drugs and assisted reproductive techniques until recently.

In the present study 90 multiple pregnancies were examined. These were subdivided on the basis of the number of embryos involved (74 twins, 10 triplets, 6 quintuplets) and on whether they were followed at our clinic for the entire pregnancy or not. In each group we analysed certain variables, calculating the respective mean values and standard deviations. We used the ANOVA test to discriminate the eventual differences in the means of the variables analysed, operating a p<0.05 significance value. In addition, significant differences were analysed by the test of Contrasts (Scheffe F-test). The concept that emerged from the data investigated is that careful management of these pregnancies, carried out in high-level structures, can reduce the incidence of complications on both the maternal and fetal side and thus prevent “minimal brain damage” in the newborn.

Multiple birth rates in entire Japan were analyzed using vital statistics for 1951 to 1988. The triplet rate was nearly constant from 1951 to 1974, where the rate per million births was 58, then increased with the year up to 1982 (104), and decreased up to 1984, and suddenly increased thereafter (109 in 1987). The average rate of quadruplets per million births from 1951 to 1968 was 0.93, then increased with the year up to 1975 (7.5), and decreased until 1984 and suddenly increased thereafter (10.6 in 1987). The rate of quintuplets was 0.77 per million births during the period from 1975 to 1987. The higher multiple birth rate since 1975 was attributed to the higher proportion of mothers treated with ovulation-inducing hormones in Japan. Since 1985, higher multiple birth rates might be partially attributed to in vitro fertilization. The stillbirth rates for male triplets gradually decreased from 1960 to 1978 and thereafter remained constant at a little higher level except in 1988, whereas the rates for females gradually decreased with the year. The overall stillbirth rates decreased to 1/4 for triplets and to 1/5 for quadruplets during the 37-year period from 1951. The overall stillbirth rate of quintuplets was 0.60 (51/85) during the period 1975-1987.

The antenatal management and outcome of 31 higher-order multiple gestations, 24 triplets, six quadruplets, and one set of quintuplets were analyzed. Bedrest was advised as soon as the diagnosis was made; hospitalization along with the administration of betamethasone and phenobarbital was begun during the second trimester. Caesarian section was performed on 13 women (42%). The overall mortality rate was 14.8%; excluding neonates less than 28 weeks of age, however, it became 7.5%. The primary cause of death was respiratory distress syndrome.