Types of statistical misuse
- Discarding unfavorable data
- Loaded questions
- Overgeneralization
- Biased samples
- False causality
- Data manipulation
The Gee-Whiz Graph
- Manipulating axes on a graph to make the results look more impressive than they are
- Not including zero on the axis
Cumulase
- Ad appeared in “family building” magazine
- Hyaluronidase is an enzyme that helps remove cumulus and there cells adhering to zona pellucida
- Used in IVF to prepare oocytes for fertilization
- Commercial preparations are extracted from bovine testes
- Cumulase is recombinant human hyaluronidase
- Cumulase is $66 per vial and hyaluronidase is $0.20 per vial
Cumulase fine print
- “an impressive 22% increase” in per patient ICSI fertilization rate over bovine extracts
- Percentage points actual difference is 15.3%
- The 22% is the increase over baseline
- Use of percentage increase versus percentage points may be confusing (intentional or not)
CDC ART Annual Report
• Includes all fertility treatment in which both eggs and sperm are handled
o Procedures involving surgically removing eggs from a woman’s ovaries, combining them with sperm in laboratory, and returning them to woman’s body or donating them to another women
• CDC ART annual report does not include
o Treatments in which only sperm are handled or procedures in which a woman takes medicine only to stimulate egg production without intention of having eggs retrieved
Jon and Kate Plus Eight
• Kate was diagnosed with PCOS
o Associated with a large cohort of follicles at any given time
• After undergoing fertility treatment Kate gave birth to twins in 2000
• Kate returned to fertility treatment again, had 3-4 mature follicles at her US prior to IUI, and gave birth to sextuplet in 2004
• Not included in CDC ART report
Raising Sextuplets
- After undergoing fertility treatment (drugs and IUI) Jenny gave birth the sextuplets in 2007
- Not included in CDC ART report
- After Delivery, Jenny suffered heart failure where she nearly died from pregnancy complications
- Jenny divorced Bryan and is no remarried to Levi- has 2 kids of his own
- Levi had a vasectomy reversal and they had a boy in 2013
When annual report comes out
• ART success rates are based on live births
o Every Art pregnancy must be followed up to determine whether birth occurred
• Earliest clinics can report complete annual data is late in year after ART treatment was initiated (about 9 months past year-end, when all births have occurred)
o Results of all cycles initiated in 2011 were not known until October 2012
• Data reporting, analysis, validation, and publication take about 1 year
Likelihood of a woman to become pregnant with ART
as age increases, number of cycles decreases
as age increases, percent of cycles resulting in pregnancies decreases
as age increases, percent of cycles resulting in live birth decreases
What is pregnancy?
- Positive hCG blood test at 4 weeks gestation
a. Measured from LMP; chemical pregnancy - Chronic sac I present at 5-7 weeks gestation
- Detection of heat beat at 7 weeks gestation
- Live birth
Pregnancy Loss
- Miscarriage rates increase in mid to late 30s and are over 65% among women older than age 44
- Most miscarriages occur prior to 14 weeks gestation
- Older women have higher rates of pregnancy loss
How successful is ART
• Not all cycles result in retrievals
o Cycle may be cancelled for poor ovarian response, illness, or other medical or personal reasons
• Not all retrievals result in transfer
o Fresh transfer may be cancelled due to poor uterine lining development, poor or no embryo development, or other medical or personal reasons
How many embryos are transferred
<35 years old: 2.0
35-37: 2.2
38-40: 2.5
41-42: 3.0
• More embryos are transferred to older women
• Approximately 6% of all transfers were eSET (elective single embryo transfer)
o Pts choose to transfer only embryo despite more being available
Does transferring more embryos increase odds of success?
• Transferring 1 embryo does not guarantee a singleton birth
• Transferring 2 embryos
o increases live birth rate by only 6.9 percentage points
o increases chance of twins or more by 39 percentage points
• Some clinics are transferring 4 or more embryos even in women under 35
Complications of Multiple Gestation or child
• Preterm birth
o Occurs in 50% of twins, 90% of triplets and virtually all quadruplet pregnancies
• Death within 1 month of birth
o 7 times more likely in twins and 20 times more likely for triplets
• Prematurity
o Increased risk of respiratory distress, intracranial hemorrhage, cerebral palsy, blindness
• Intrauterine growth restrictions, intrauterine death of one or more fetus, miscarriage, congenital anomalies are common
Complications of Multiple gestation for mother
• Pre-eclampsia is 3-5 times more likely than for singleton pregnancy
o Can be life threatening
• Premature labor requiring prolonged bed rest is common
• Placental abnormalities and maternal hemorrhage are more likely to occur
• Gestational diabetes, anemia, excess amniotic fluid are common
• Cesarean-section is often needed for twin pregnancies and almost all triplet pregnancies
Octomom
- Dr. Kamrava was originally said to transfer 6 embryos but actually transferred 12
- Lost his medical license in CA
- Octuplets were born 30.5 weeks gestation weighing between 1 lb 8 oz and 3lbs 4oz
- 46 physicians and staff assisted in delivering the octuplets
- One estimate calculates cost of 600,000 for hospitalization of octuplets, not including cost of deliverie
Preemies
• Amillia Taylor was born at 21 weeks 6 days old
o Based on IVF date not LMP so there is controversy over actual date
• Weighed 10 oz at birth
• Babies born less than 23 weeks and 14 oz are not considered viable
• Survival rate for baby born at 23 weeks and weighing 16 oz is 30%
• Amilias survival may have effect on abortion debate
Percentage of ART babies conceived from donor eggs
- Percentage of cycles using donor eggs increased sharply after age 40
- 88% of all ART cycles after age 48 used donor eggs
- Donor eggs were used in approximately 12% of all ART cycles performed in 2011
- No national data collected for babies conceved from donor sperm
- Estimates range from 30,000-60,000 per year to 75,000 per year
