Lecture 5: Maternal Weight Gain Flashcards
How much does a baby weigh at birth generally?
3.5kg
What is ‘normal’
birthweight?
2.5-4kg
How much maternal fat stores does a mother have at birth?
Approx. 3.5kg
Why do mothers need fat stores?
Stored energy for healing and breastfeeding
What is the recommendation for weight gain during pregnancy if you are starting at a healthy weight (BMI=18.5-24.9)?
11.5-16kg
What is the recommendation for weight gain during pregnancy if you are starting as overweight (BMI=25-29.9)?
7-11.5kg
What is the recommendation for weight gain during pregnancy if you are starting as underweight (BMI= <18.5)?
12.5-18kg
Why do pregnant women need to maintain healthy weight gain?
Ensure babies are born within the normal range
Weight gain increases as…
Pregnancy goes on (mostly in 2nd and 3rd trimester)
What is the mean weekly weight gain for women of healthy BMI in 2nd and 3rd trimesters?
0.42 (0.35-0.5) kg/week
When should pregnant womens BMI be measured?
From a pre-pregnancy weight or an early pregnancy weight (ideally <10 weeks gestation)
What is the recommendation for weight gain during pregnancy if you are starting at a healthy weight (BMI=18.5-24.9) for TWINS?
17-25kg
What is the recommendation for weight gain during pregnancy if you are starting as overweight (BMI=25-29.9) for TWINS?
14-23kg
What is GWG?
Gestational weight gain
What is gestational weight gain made up of?
- Fetus
- Water
- Fat mass
- Fat-free mass
How much of GWG is water?
62%
How much of GWG is fat mass?
30%
How much of GWG is fat-free mass?
8%
How much of GWG is the fetus?
25%
How much of fetal growth occurs in the second half of pregnancy?
90%
What does fetal weight gain look like over the pregnancy?
Starts around 12 weeks, grows more in the 2nd and 3rd trimester
What does mothers weight gain look like over the pregnancy?
Starts around 8 weeks, mothers gain is a steeper slope compared to fetus
How much of GWG occurs in 2nd trimester?
1/3
How much of GWG occurs in 3rd trimester?
2/3
What weeks are maternal fat stores gained predominantly between?
10th-30th week
What does 1st and 2nd trimester weight gain reflect?
Deposition and expansion of maternal tissue
What does late 2nd trimester onwards weight gain reflect?
Primarily fetal, placental and accumulation of amniotic fluid
What are the NZ guidelines for pre-pregnancy weight gain?
Focus on obese women - We really want the mother to start their pregnancy at a healthy weight
What is higher BMI and lower education associated with during pregnancy?
Greater GWG
Overweight and obese women are more likely to…
Overestimate appropriate weight gain
What is the PA guidelines for pregnant women?
30 mins moderate intensity physical activity atleast 5 times a week
What does postpartum weight retention look like?
A lot of GWG is retained, meaning preconception BMI will be increased
What does retained GWG look like in later life?
Increased BMI, fat mass and visceral fat
What percent of adults in the world carry excess weight?
39%
Obese women vs lean women; risk of miscarriage and stillbirths
Obese women have a 25-37% higher risk
What is PIH?
Pregnancy-induced hypertension; also known as toxemia or pre-ecampsia (high BP developing after 20 wks gestation)
What is venous thromboembolism?
Blood clot within vein (thrombosis); if transported, embolism travels to right side of heart and into lungs (pulmonary embolism) - can be fatal
What are examples of delivery complications?
Labour induction and caesarean delivery
What is GDM?
Gestational diabetes mellitus
What are the implications of obesity for pregnant women?
- Miscarriage/stillbirths
- Pregnancy-induced hypertension (PIH)
- Venous thromboembolism
- Delivery complications
- Gestational diabetes mellitus (GDM)
What are the odds of cesarean delivery in women above recommended weight gain?
1.3 times greater
What is Gestational Diabetes Mellitus (GDM)?
A condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy - generally very few symptoms
How many pregnancies does GDM affect?
3-10% of pregnancies
How many cases of diabetes in pregnancy are GDM?
90% of cases
How many NZ women are diagnosed with gestational diabetes per year?
3000-4000
What does the prevalence of GDM look like over time?
Prevalence is increasing 8-9% per year, relative to the increasing rates of obesity
What does the prevalence of GDM look for different ethnicities in NZ?
- Maori (5-10%)
- Pacific peoples (4-8%)
- Asian Indians (4%)
- NZ Europeans (3%)
How does GDM happen?
Unknown - believed that hormonal changes interfere with the action of insulin as it binds to the receptor resulting in increased insulin resistance
Is GDM reversible?
Yes with adequate control of blood glucose
What are the risk factors for GDM?
- Overweight (2.1x), Obese (3.6x) and Severely Obese (8.6x)
- Previous diagnosis of diabetes related illnesses
- Family history
- Age (esp. over 35)
- Previous child with high birth weight
What are the complications for the baby caused by GDM?
High maternal blood glucose exposes the fetus to higher glucose levels; leads to increased fetal levels of insulin
What are the effects of high fetal insulin levels?
Growth stimulating effects of insulin can lead to excessive growth and macrosomia (fetal overgrowth) = high risk of developing T2D later in life
What are the complications for the mother caused by GDM?
- Higher risk of developing GDM again
- Increased risk of T2D
- Caesarean section
- Induction of labour
What is the recommendation for NZ to screen for GDM?
All non-diabetic women offered/recommended screening for GDM
How is GDM screened for?
- Blood test before 20 weeks
- Oral glucose tolerance test (OGTT) recommended at 24-28 weeks
What are implications of maternal obesity for the baby?
Increased risk of congenital abnormalities
What are congenital abnormalities?
structural or functional defects that occur during intrauterine development - present from birth
What kind of congenital abnormalities does maternal obesity cause in babies?
CNS and heard including:
- CV defects
- Orofacial clefts
- Hydrocephalus
- Limb reductions
For every incremental unit increase in BMI (of mother) the risk of birth defects increases by….
7%
What are the odds of NTD to babies born to obese mothers?
1.6 greater odds
What is SGA?
Small for gestational age
What is the cut off for SGA?
Birth weight below the 10th percentile for age
What is LGA?
Large for gestational age
What is the cut off for LGA?
Birth weight above the 90th percentile, for age
What is macrosomia?
growth beyond a specific threshold, regardless of gestational age
What is macrosomia in pregnancy?
> 4000g
What does the delivery of infants with birth weight more than 4000g increase risk of?
- Caesarean delivery
- Fetal hypoglycaemia
- Shoulder dystocia
What is a neonate?
New baby
What is the risk of death 18 months post birth for pre-term infants born to obese mothers?
4 times greater than for lean mothers
What is the recommendation for weight loss during pregnancy?
Not recommended