This seems counterintuitive, but turns out that as infant mortality is reduced, population sizes also decrease, because parents don't need to anticipate that their babies are going to die.
Hal ini tampak tidak masuk akal, namun pada kenyataannya saat tingkat kematian bayi menurun jumlah populasi juga menurun, karena orang tua tidak perlu mengantisipasi kemungkinan meninggalnya bayi mereka.