In developed countries stillbirth — or death of a fetus after 20 weeks of gestation — occurs in HELLP syndrome in 51 out of every 1000 pregnancies, a rate that, according to the Preeclampsia Foundation, is higher than in severe preeclampsia and eclampsia (when preeclampsia progresses to cause seizures). (romper.com)
This shows that stillbirth happens usually 3 — 5 weeks before the woman reaches full term and also that for sextuplets or higher it almost always ends in death of the fetuses. (en.wikipedia.org)