1. Maternal cardiac function in twin pregnancies compared with singleton pregnancies.
Makiko Kato, Yu Yaegashi, Shinji Monoe, Takuji Ueno, Takuma Yamada, Takehiko Takeda, Sho Tano, Kaname Uno, Michinori Mayama, Mayu Ukai, Teppei Suzuki, Yasuyuki Kishigami and Hidenori Oguchi
Department of Obstetrics, Perinatal Medical Center,
TOYOTA Memorial Hospital, Aichi, Japan

2. Disclosure of conflict of interest
We have nothing to declare for this study.

3. Background
The maternal cardiac system undergoes significant changes throughout pregnancy, and twin pregnancies are exposed to more significant hemodynamic changes than singleton pregnancies.
These physiological changes impose considerable stress on maternal hearts and increase the risks of pulmonary edema and peripartum cardiomyopathy (PPCM).

4. Background
The current definition of PPCM only includes patients with left ventricular systolic dysfunction.
Some authors presented cases of peripartum heart failure with normal EF and raise the possibility that the definition of PPCM be expanded to include left ventricular diastolic dysfunction1).
Data on diastolic dysfunction in twin pregnancies are sparse.
1) Afonso et al:Comparison of Patients With Peripartum Heart Fairule and Normal(≧55%)
Versus Low(<45%) Left Ventricular Ejection Fractions:Am J Cardiol 2014;114:

5. Objective
To reveal the changes in cardiac function in twin pregnancies compared with singleton pregnancies.
To investigate if twin pregnancies carry considerable risks of heart failure or PPCM caused by diastolic dysfunction.

6. Material and Methods Study Design A single perinatal medical center,
prospective cohort study.
A total 142 twin pregnant women and 44 singleton pregnant women were enrolled in this study.
21 twin pregnant women were excluded due to preeclampsia or history

7. Singleton pregnancies
Material and Methods
Twin pregnancies
(n=145)
Singleton pregnancies
(n=44)
Enrolled (n=121)
Not suitable for study:
Intrauterine fetal death
at least 1 baby (n=1)
Development of preeclampsia (n=23)
A total 142 twin pregnant women and 44 singleton pregnant women were enrolled in this study.
21 twin pregnant women were excluded due to preeclampsia or history

8. Material and Methods
Trans-thoracic echocardiography and serum brain natriuretic peptide (BNP) levels were examined at early, middle, late pregnancy, within 5 days after delivery, and at one-month postpartum.

9. Methods Trans-thoracic echocardiography
Left ventricular ejection fraction (LVEF) was measured to evaluate systolic function. LVEF<55% was defined as systolic dysfunction.
Early transmitral velocity/early diastolic velocity of the mitral annulus (E/E’) was measured to diastolic function. E/E’<8 was defined as normal diastolic function.

10. Maternal Cardiac function of singleton pregnancies and twin pregnancies

11. Maternal Cardiac function of singleton pregnancies and twin pregnancies

12. Maternal Cardiac function of singleton pregnancies and twin pregnancies

13. Maternal Cardiac function of singleton pregnancies and twin pregnancies

14. Maternal Cardiac function of singleton pregnancies and twin pregnancies

15. Result
In twin pregnancies, diastolic function deteriorates in late pregnancy and early postpartum, whereas systolic function maintains through all periods.
Serious BNP level is relevant with diastolic deterioration, so it has the potential to being used as a valuable marker of diastolic dysfunction.

16. Discussion
In twin pregnancies, compared with singletons, maternal cardiac output is higher by 20-40%2).
This greater hemodynamic change could be considered to be a risk of cardiac dysfunction in twin pregnancies.
To date, whether twin pregnancies are associated with future cardiovascular disease are controversial.
2) Kametas et al: Maternal Cardiac Function in Twin Pregnancy:
The American College of Obstetricians and Gynecologists.Vol.102,NO.4,OCTOBER 2003:

17. Discussion
According to our study, diastolic dysfunction in twin pregnancies was showed temporarily and it reverted after one month delivery.
This result suggests that twin pregnancies may not be a risk factor of future cardiovascular disease.

18. Conclusions
In twin pregnancies, because theirs diastolic function deteriorates in peripartum period, they are required careful attention especially during that period.
BNP may be a helpful marker to evaluate diastolic function.