Gestation and the marriage market: second child still takes nine months

How long (after marriage) it takes for the first child to arrive is determined by many complex things, but the marriage market in Japan is evolving in a direction that shortens the time: Shotgun weddings on rise in Japan as attitudes to pregnancy shift.

"“From about five years ago the number of dekichatta-kon [weddings due to pregnancy] that we handle has not stopped rising,” she said. “Last year we worked out that about a quarter of the brides we worked with were pregnant, and some were about eight months along when they tied the knot.
“The couples used to be embarrassed, and our job was to try to hide the fact from the families. Now everyone is so relaxed about it we try to turn it into a double celebration and make life as easy as possible for the mother-to-be.”
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"The shift reflects changing attitudes in Japan. The historic taboo of pregnancy outside marriage was largely abandoned during the 1990s but a strong tradition of being married by the time of the birth remained.
By 2004, however, the national average of ten months between marriage and the birth of a first child had fallen to six. "