[cdc office of womens health, health matters for women] declines in triplet and higher order multiple births in the united states, 1998 2014 /

The incidence of triplet and higher-order multiple births rose fourfold during the 1980s and 1990s (1-3). This rise was associated with older maternal age and the increased expend of fertility-enhancing therapies (4,5) and was of concern because of the greater risk of adverse outcome of triplet and higher-order births compared with singletons and the added toll of these pregnancies on maternal health (6). Since 1998, however, or this trend has edged downward (3).

Source: cdc.gov