Supertwins Statistics

MOST Medical Birth Survey Data

Statistics Current to June 2007

Primary researcher: Kelly Ross, MD Instructor, Division of Newborn Medicine Washington University School of Medicine, Pediatric Hospitalist at St. Louis Children’s Hospital, MOST Medical Director

Additional researchers: Maureen A. Doolan Boyle, MOST Executive Director; Elizabeth Pector, MD, FAAFP, MOST Advisory Board; Laurie LaMonde Ph.D, Clinical Psychologist;  Kate Collopy, Ph.D., RN, CCNS Bioethics; Karen Lohan, RN FAAFP, MOST Advisory Board; Lauretta Shokler, MOST Technology Director

The MOST Medical Birth Survey is a longitudinal study started in 1988. The survey collects data pertaining to socio-demographic status, medical, gynecologic, and obstetric history, pregnancy, perinatal, and neonatal events. The survey also gathers information regarding breastfeeding and ongoing developmental and medical challenges in multiple birth children. The database of responses currently contains over 1800 participants and over 5800 infants. This survey is one of the most comprehensive and extensive databases on multiple births in the world.

MOST believes this data reflects the high-risk nature of higher order multiple births, but will also reassure couples who are expecting triplets, quadruplets, and more, that a healthy outcome is possible for the majority of higher-order multiples. While higher order multiple births are without question more complicated than single births, with the help of a perinatologist experienced with working with higher order multiple pregnancies, the majority of women give birth to infants who grow to be healthy, developmentally normal children.

For example, one year survival rates for the multiple births represented in the MOST Birth Survey are as follows:

97.2% of triplets
87.0% of quadruplets
48.1% of quintuplets
50.0% of sextuplets

 

 

54.6 % of triplets were born after 34 weeks.
55.5 % of quadruplets were born after 32 weeks.
57.7 % of quintuplets were born after 30 weeks.

 

 

Multiple Type	# of surveys	# of infants	% of respondents
Twins	13	26	0.72%
Triplets	1504	4512	82.82%
Quadruplets	238	952	13.11%
Quintuplets	52	260	2.86%
Sextuplets	7	42	0.39%
Septuplets	2	14	0.11%

 

Note: Due to the small number of surveys received for twins, sextuplets, and septuplets to date, MOST may publish some categories of statistics for these respondents in order to protect their privacy and confidentiality. However, MOST does make this data, without identifying information, available on a case-by-case basis to medical professionals who make a request to care for current patients. To learn more about MOST research and respondent privacy, please see MOST's Privacy Policy.

 

 

By comparison, the average age of an American woman at the time of her first birth:

 

 

is 25.1 years old*

has a median weight gain of 30 pounds*

81% will deliver after 37 weeks gestation*

the average birth weight for singletons is 7 lbs. 6 oz.*

(*Source: Birth data for 2002, National Vital Statistics Report, Center for Disease Control and Prevention)

 

Marital Status	Percent
Married	95.8%
No Answer	1.8%
Divorced or Separated	0.9%
Single or Engaged	0.8%
Partnered	0.4%
Widow or Widower	0.3%

 

Learn more about marriage and multiple births from

MOST's Divorce and the Multiple Birth Family survey.

 

The MOST birth survey shows a corresponding increase in multiples' birth weights as a mother's height increases. However, the survey does not show a consistent rise in infant birth weight in association with higher maternal pre-pregnancy weights, nor did a higher maternal height correspond with a longer pregnancy gestation. (see table below)

 

Influence of Maternal Weight and Height on Infant Birth Weight
Mother's Weight Range	Average Infant Birth Weight	Mother's Height	Average Infant Birth Weight
Under 100 lbs	3 lbs 8 oz	4' 10"	2 lbs 15 oz
100-120 lbs	3 lbs 13 oz	4' 11"	2 lbs 15 oz
120-140 lbs	3 lbs 15 oz	5' 0"	3 lbs 9 oz
140-160 lbs	4 lbs 0 oz	5' 1"	3 lbs 13 oz
160-180 lbs	3 lbs 14 oz	5' 2"	3 lbs 11 oz
180-200 lbs	3 lbs 15 oz	5' 3"	3 lbs 13 oz
200-220 lbs	4 lbs 1 oz	5' 4"	3 lbs 14 oz
220-240 lbs	3 lbs 12 oz	5' 5"	3 lbs 15 oz
240-260 lbs	3 lbs 10 oz	5' 6"	3 lbs 15 oz
260-280 lbs	3 lbs 7 oz	5' 7"	4 lbs 1 oz
280-300 lbs	4 lbs 4 oz	5' 8"	4 lbs 0 oz
Over 300 lbs	4 lbs 0 oz	5' 9"	3 lbs 15 oz
To calculate an estimated birth weight based on current gestation and type of multiples, visit MOST's online birth weight calculator.		5' 10"	4 lbs 6 oz
		5' 11"	4 lbs 2 oz
		6' 0"	4 lbs 5 oz
		6' 1"	5 lbs 1 oz

 

The overall age range for all mothers in the MOST birth survey is 19 to 48 years old.

Mothers expecting multiples in their thirties have slightly longer pregnancies and heavier birth weights. (see table below)

 

Maternal Age Range	Average Gestation	Infant Birth Weight
Under 30 years	32.08 weeks	3 lbs 11 oz
30-39 years	32.95 weeks	4 lbs 0 oz
40 years or older	32.14 weeks	3 lbs 12 oz

 

 

 

30.7% of respondents had a history of miscarriage.

2.3% of respondents had a history of stillbirths.

 

Mothers who give birth prior to their multiple pregnancy, have longer gestations: (see table below)

 

 

 

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Please support this valuable research by donating to MOST today.	Other MOST Medical Birth Survey Data
	Pregnancy Delivery Post-Partum Breastfeeding	Infants Triplet profile Quadruplet profile Quintuplet profile Sextuplet profile

 

Updated 7/20/09