The longest confirmed time between the birth of twins is 87 days. Maria Jones-Elliott went into premature labor and delivered her daughter Amy, who weighed just 1 pound 3 ounces. Her twin sister Katie stayed in the womb for nearly three more months, arriving 87 days later. This case, which took place in Ireland, is recognized as the world record for the longest interval between twin births.
While 87 days is the most widely cited record, medical literature documents delays of up to 152 days in multi-fetal pregnancies. The vast majority of twins are born minutes or hours apart, so any gap measured in days is extraordinary. These prolonged intervals don’t happen by accident. They require a deliberate medical strategy called delayed interval delivery.
How Delayed Interval Delivery Works
In a typical twin birth, the second baby arrives within about a day of the first. But when the first twin is born dangerously early, sometimes before 24 weeks of pregnancy, doctors may try to keep the second twin in the womb long enough to improve its chances of survival. This approach is called delayed interval delivery, and it turns what would normally be a crisis into a controlled waiting game.
For this to even be an option, several conditions need to be met. The twins must each have their own amniotic sac (a shared sac would rupture during the first delivery). The membranes around the remaining twin must still be intact. There can be no signs of infection in the uterus, and neither the mother nor the remaining baby can have a condition that requires immediate delivery. When all of these line up, the medical team essentially pauses the birth process.
After the first baby is delivered, the umbilical cord is tied off high and the placenta is typically left in place. The cervix may close on its own, or in some cases doctors will place a stitch to help hold it shut, though this remains controversial because of infection risk. The mother receives antibiotics and is monitored closely for any sign of complications. If delivery of the second twin appears imminent, medications to protect the baby’s brain and accelerate lung development are given beforehand.
How Long the Delay Typically Lasts
Most delayed interval deliveries don’t come close to the 87-day record. Data from one perinatal center covering 17 years of cases found the average delay between twins was 19 days, with a range of 1 to 107 days. The medical literature overall reports delays ranging from 1 to 152 days, though the longer intervals are rare and tend to occur in cases where the first twin was born very early.
The gestational age at the first delivery matters enormously. When the first twin arrives before 25 weeks, there’s more time to gain and more reason to try. After 25 weeks, the potential benefit shrinks because the second twin is already closer to viability, and the delays in those cases tend to be much shorter, often less than two weeks.
Why Extra Time Makes Such a Difference
Every additional day in the womb at extremely early gestational ages can meaningfully improve a baby’s chances. A systematic review covering 128 cases of delayed interval delivery found that the second-born twin had significantly lower mortality than the first-born twin. The second baby’s risk of death was less than half that of the first. This held true even when the analysis was limited to cases where the first delivery happened at or after 24 weeks.
The long-term outlook is encouraging too. One study that tracked outcomes for the second-born babies and compared them to other children born at the same gestational age found no meaningful difference in long-term health. In other words, the delay itself doesn’t appear to cause additional problems beyond what you’d expect from prematurity.
Risks to the Mother
Carrying one twin while the other has already been delivered is not without danger. The primary risks are uterine infection and maternal sepsis, both of which can develop because the cervix has already dilated and the first twin’s placenta may still be inside the uterus. During the waiting period, doctors monitor for signs of infection, recurring contractions, placental separation, and blood clotting disorders. If any of these develop, the second twin is delivered immediately regardless of gestational age.
Twins Born in Different Years
Not every unusual twin birth interval involves a medical emergency. Some twins simply have the luck of arriving on either side of midnight on December 31. In one well-known case from California, fraternal twins Alfredo and Aylin Trujillo were born just 15 minutes apart, but Alfredo arrived at 11:45 PM on New Year’s Eve 2021, and Aylin followed at midnight on January 1, 2022. The hospital estimated the odds of twins being born in different calendar years at roughly one in two million. These cases are a fun quirk of timing rather than a medical feat, but they capture public attention for the same reason the 87-day record does: the idea that twins, who shared a womb, can end up with strikingly different birthdays.