 Family size in the colony was large by modern American standards , though childbirth was often spaced out , with an average of two years between children . Most families averaged five to six children living under the same roof , though it would not be uncommon for one family to have grown children moving out before the mother had finished giving birth . Maternal mortality rates were fairly high ; one birth in thirty resulted in the death of the mother , resulting in one in five women dying in childbirth . However , " the rate of infant mortality in Plymouth seems to have been relatively low . In the case of a few families for which there are unusually complete records , only about one in five children seems to have died before the age of twenty @-@ one . Furthermore , births in the sample [ of about 90 families ] come for the most part with relatively few ' gaps ' which might indicate a baby who did not survive . All things considered , it appears that the rate of infant and child mortality in Plymouth was no more than 25 per cent " . 
