When you are expecting a big baby, your caregivers may have two major concerns: cephalopelvic disproportion, and shoulder dystocia.
"Cephalopelvic disproportion" means that the baby's head may be too large to fit through your pelvis. However, this is not usually an emergency situation, as long as you do seek help when it becomes clear that the labour is not going anywhere. See "Your pelvis may be too small..." for more discussion. If your baby's head is too large, your labour will simply not progress, and you will need to transfer to hospital. Worries about this should not necessarily stop you booking a home birth, as the freedom to move at home means that you will be able to give your body the best chances of opening up and allowing your baby to be born.
The second major concern is shoulder dystocia. This means "stuck at the shoulders" and it occurs when the baby's head is born, but its shoulders are trapped inside the mother's pelvis. True shoulder dystocia is very rare, but when it occurs, it can be fatal for the baby. However, it is less of a worry at home births than at hospital births, for reasons which I will explain below.
The discussions of shoulder dystocia have been moved to a separate page because they are long and technical. I will copy here the introduction to topics on there which are generally relevant to large babies and home birth.
Elective caesarean section is sometimes recommended for suspected large babies to avoid the possibility of shoulder dystocia. However, the majority of recent research concludes that this is not advisable - the evidence does not support this intervention. Please see the Shoulder Dystocia page for a list of references.
Again, the evidence suggests that induction at term is not the best way to avoid birth trauma for suspected large babies. It increases the caesarean section rate, and associated problems, for mother and baby, but does not reduce the shoulder dystocia rate, nor does it improve outcomes. See the Shoulder Dystocia page for a list of references.
One of the problems with having a 'suspected' large baby is that the suspicions of ultrasound operators and midwives may be wrong.
Ultrasound may overestimate fetal weight in general, and is hit-and-miss at the best of times - eg one study  found that the estimated weight was heavier than the actual birthweight in 66 out of 86 women studied (77%). And the estimated weight was only within 500g of the actual weight for 41 of these 86 women. Bear in mind that 500g is over 1lb!! That's a big margin for error...
A special UK government report (CESDI - ) looked at deaths of large babies (4000g and over), and it concluded that ultrasound estimation of fetal weight was NOT recommended where a large baby was suspected, because "the inaccuracy of ultrasound estimates have been well documented. Indeed, it is possible that estimating fetal weight by late ultrasound may do more harm than good by increasing intervention rates" (p47).
CESDI also quote research concluding that elective induction and elective caesarean for suspected large babies are not recommended, although suggest that large randomised controlled trials are needed. Their main recommendation is that, where a large baby is suspected, the attendants should be on the alert for a delay in late labour, which could be a warning sign for shoulder dystocia.
Amanda L is only 5'2", but she still managed to push her 10lb 5oz baby out under her own steam, at home.
Sarah was advised against a home birth for her third baby, because her first two weighed 9lb 12oz and 10 lb. Nonetheless, Rafferty arrived safely, in a birth pool, weighing 11lb3oz, and he was followed in 1997 by Violet, at 11lb 1oz!
Dawn's second baby was born at home weighing 9lb 8oz, after a very rapid second stage. He had 'sticky' shoulders and was floppy when born, but soon perked up.
Joy Mottram's second baby, Malachi, was born at home at 43+3 gestation, weighing 10lb7oz.
Jackie Shute's third baby was born at home weighing 10lb - a very straightforward, positive birth story.
Julie Kennedy's second baby was born at home weighing 9lb 9oz. Her first baby, 15 years earlier, had been delivered by forceps, but Julie did not need any intervention to deliver Emma.
Donna Freeman had to stand her ground when a midwife questioned the suitability of homebirth because her baby might be big. Donna writes: "I'm immensely proud of myself that I stood up for what I wanted and created a situation that led to a 'perfect' birth. I'd do it all again tomorrow, just to live through it again." . George weighed in at 8lb 12oz (about 4Kg)
Debbie Dooley's fifth baby was born at home weighing 9lb 5oz. Debbie is an insulin-dependent diabetic, and she researched her birth choices extremely carefully.
Kirsty Nicol's second baby was, at 9lb 4oz, nearly half as big again as her first!
Christy gave birth to her 10lb son completely alone.
Rachel Hale gave birth to her 8lb 13oz first baby, Jude, at home in water.
Peta's fifth baby, Melee, weighed nearly 10lbs and she suffered severe shoulder dystocia. She was resuscitated effectively at home, but later transferred to hospital because of concerns about her breathing.
Kathryn's fourth baby was born at home, 20 days after his due date, weighing 9lbs. Oh, and he was breech too....
Debbie was dreading the pushing stage after a tough hospital birth with her first 9lb + baby - but in the event it lasted all of 10 minutes, for most of which Debbie was in denial! Lovely, straightforward birth of another 9lb-er.
Jane had two caesareans, five hospital VBACs, and two ectopic pregnancies before she gave birth to her seventh and eighth babies at home. This is the story of 9lb 2 1/2 oz Caitlin's birth.
Doris's seventh baby, Gabrielle, was born at home weighing 11lb 12ozs and, although Doris was on all-fours to give birth, her baby's shoulders stuck. McRoberts' maneouvre was used to help her deliver the baby's shoulders.
Jeanette Archer 'breathed' out all 9lb 12oz of her third baby, Angus, and three years later had another homebirth with 10lb 14 1/2 oz Sidney. Sidney's shoulders were a little slow to appear, so Jeanette's midwives put her in the McRoberts position, which was immediately effective.
Gillian's third baby, Lewis, weighed 9lb 2oz. Her first weighed 7lb 14oz, and her second was 8lb 5oz.
Oddny's second baby, Anton, weighed just over 9lb, and he was an unexpected footling breech presentation. Despite this, Oddny gave birth to him naturally and gently, after a labour of just two and a half hours.
Jessica's third baby, Adie, weighed 10lb 3 1/2 oz. Although her shoulders were fine, she was a little stuck at the tummy, and needed some resus after the birth - but was fine.
Keri's third baby, Ian, was born at home - all 10lb 6oz of him!
Anna's second baby was born at home weighing 9lb 4 oz - and he was breech.
Jo had an unplanned, rapid homebirth of her 11lb 10oz baby, with shoulder dystocia. Her son needed resuscitation after birth, and they transferred to hospital to be checked over. Fortunately he was OK.
Catriona's third baby, Benjamin, was born at home weighing 9lb 3oz.
Danielle Winser's first baby was born at home weighing 10lbs. Lovely labour and excellent support.
Ziva's birth story is a lovely example of how a petite mother (4'11" tall) can give birth to a large baby (8lb 9oz) perfectly naturally. There was some shoulder dystocia, but it resolved as Ziva's mother climbed out of the birth pool.
Becky Wilsdon's first baby, Sam, arrived by home waterbirth. He weighed 9lb 1 oz, but Becky managed to deliver him without intervention, and with only a minor tear.
Cerys Byrne's third baby, Alexander, was born at home, in water, on 3rd August 2003. He weighed 9lb 5oz.
Sarah Sadler's second baby, Freya, was born at home weighing 9lb 9oz. This was despite a doctor muttering that Sarah's hips were 'too small' when she transferred to hospital for the forceps delivery of her first baby, who was 8lb 1 oz.
Catherine Rogers's first baby was born in hospital, weighing 6lb 7oz. Her second and third were born at home, weighing 9lb 1.5 oz and 9lb 14oz.
Joanne Foster's third baby, Harry, weighed 9lb 5 oz. Despite having had a third-degree tear with her much smaller first baby, Joanne needed no stitches after Harry's home birth.
Rachael's second baby, Archie, was born at home weighing 9lb 4oz.
Nichole Bruce's third baby, Adam, was born at home weighing 9lb 4oz.
Hatty Wilson's fourth baby, Seren, was born safely at home weighing 11lb 12oz, at 43 weeks and 2 days' gestation.
Louisa Todd's second baby, Joe, was born at home weighing over 10lbs; her first, Ellie, was a ventouse delivery.
Andrea had her tenth baby, Seth, at home - weighing over 11lbs. Seth's was a planned, unassisted birth.
Laura Bentz's first baby, Iain, was born by caesarean section weighing 10lbs; there were always some concerns that perhaps he was 'too big' to be born, although his head was not in the ideal position. Laura's second baby, Clara, was born at home, weighing 11lbs.
Julia De Lucchi's third baby, Hudson, arrived weighing 10lbs in a home waterbirth.
Kirsten Millinson had two babies at home, after a traumatic hospital birth with her first baby. Her third baby weighed 10lb 5oz.
Jennifer Vaudin's second baby, William, was born at home weighing 4.3Kg (approx 9lb 7oz)
Angela Horn's first baby, Lee, was born at home weighing 9lb 6oz (4.25 Kg)
Katie Davis had planned a home birth for her second baby, but had an 'accidental' (!!) hospital birth - with no intervention. Kira weighed 10lb 7oz.
Tikki Potter's third baby was born at home weighing 9lb 2oz, and her fourth, Simon, weighing 9lb 8oz.. Tikki's first baby was born by forceps delivery, her second by caesarean section.
Joanne King's first baby, Ethan, was born at home weighing 9lb 1oz.
Steph's second baby had a lovely, gentle homebirth weighing 9lb 1oz.
Sarah Calvert "breathed out" her second baby gently and calmly, and despite the fact that he weighed 9lb 2oz she had an intact perineum and minimal blood loss.
Genevieve was told by an obstetrician that her first baby would be 4-5Kg, but in fact she was only 3.4 Kg.
Ruth Gallagher's first baby, Hazel, was born at home weighing 9lb 10oz, six days after her waters broke. Her second, Robbie, was 12lb (5.45 Kg), and was 3 weeks post-dates. Ruth is only 5 feet 3 inches tall.
Alison Tooth's third baby, Elijah, was born at home in the UK, weighing 9lb 11oz.
Anna planned a home birth for her first baby, but was persuaded to transfer to a hospital booking by a midwife and GP, because her baby was expected to be large. She had a planned caesarean instead, which ended in an emergency hysterectomy. Her baby was 8lb 12oz.
Monika and Larry McMahan's second child, in the USA. Includes wonderful photos of the birth. 10lb 6oz baby born with his hand stuck up by his face.
Ann O'Ceallaigh, a midwife in Ireland, displays the stories of several mothers she has attended, including one who had a 12lb baby!
 Pregnancy outcome following ultrasound diagnosis of macrosomia.
AUTHORS: Delpapa EH; Mueller-Heubach E
AUTHOR AFFILIATION: Department of Obstetrics and Gynecology, University of Pittsburgh, Magee-Women's Hospital, Pennsylvania.
SOURCE: Obstet Gynecol 1991 Sep;78(3 Pt 1):340-3
Extract: "In 66 of 86 women (77%) delivering within 3 days of ultrasound examination, estimated fetal weight (EFW)exceeded birth weight. In only 41 of these 86 women (48%) were the EFWs within the corresponding 500-g category of birth weight"
 The 6th Annual CESDI report(Confidential Enquiry into Stillbirths and Deaths in Infancy, published by UK government)
Available free online at the Confidential Enquiry into Maternal and Child Health website (www.cemach.org.uk)
 5th Annual CESDI (Confidential Enquiry into Stillbirths and Deaths in Infancy) - HMSO
Available free online at the Confidential Enquiry into Maternal and Child Health website (www.cemach.org.uk)
Home Birth Reference Page