Editing Twin (section)

==Delivery interval==
A 15-year German study<ref name="acta">{{cite journal |vauthors=Stein W, Misselwitz B, Schmidt S |title=Twin-to-twin delivery time interval: influencing factors and effect on short-term outcome of the second twin |journal=Acta Obstet Gynecol Scand |volume=87 |issue=3 |pages=346–53 |date=2008 |pmid=18307076 |doi=10.1080/00016340801934276 |s2cid=19195460}}</ref> of 8,220 vaginally delivered twins (that is, 4,110 pregnancies) in [[Hesse]] yielded a mean delivery time interval of 13.5 minutes.<ref>There were 836,104 deliveries of babies in Hesse over the 15-year study period, including 11,740 twin pregnancies, of which only 4,110 met the inclusion criteria and hence were examined in the study. The excluded twin pregnancies were in cases of (1) delivery before 34 weeks of gestation; (2) when the first twin was delivered by [[caesarean section]]; (3) when either of the twins had died in the womb before the onset of labor; and (4) when the pregnancy had been complicated by fetal malformations or [[Twin-to-twin transfusion syndrome]].</ref> The delivery interval between the twins was measured as follows:
* Within 15 minutes: 75.8%
* 16–30 minutes: 16.4%
* 31–45 minutes: 4.3%
* 46–60 minutes: 1.7%
* Over 60 minutes: 1.8%

The study stated that the occurrence of complications "was found to be more likely with increasing twin-to-twin delivery time interval" and suggested that the interval be kept short, though it noted that the study did not examine causes of complications and did not control for factors such as the level of experience of the obstetrician, the wish of the women giving birth, or the "management strategies" of the procedure of delivering the second twin.

There have also been cases in which twins are born a number of days apart. Possibly the worldwide record for the duration of the time gap between the first and the second delivery was the birth of twins 97 days apart in Cologne, Germany, the first of which was born on November 17, 2018.<ref>{{cite news |url=https://www.thetimes.com/world/article/i-ll-do-it-my-way-twin-is-born-three-months-after-her-sister-f3jkjp72q |title=I'll do it my way: twin is born three months after her sister |work=The Times |last=Crossland |first=David |date=16 April 2019 |access-date=9 July 2021 |url-access=subscription |archive-date=30 August 2021 |archive-url=https://web.archive.org/web/20210830143642/https://www.thetimes.co.uk/article/i-ll-do-it-my-way-twin-is-born-three-months-after-her-sister-f3jkjp72q |url-status=live}}</ref>