Table 1

Characteristics of included Prospective Cohort Studies

Study/Year of Publication Reference (country)

Participants

Intervention

Outcome

Risk of Bias (Notes)


Garcia-Patterson 1997 [20](Spain)

66 participants with type I and type II who attended the preconception clinic and 119 participants with type I and type II diabetes who did not.

PCC included intensive insulin therapy, self-monitoring of blood glucose and dietary advice

The HA1C was significantly better in the PCC group than for the NPCC group (p = 0.01). The rate of cesarean section was higher in the PCC group than the NPCC. No differences were observed in abortion, Pre-eclampsia and preterm labor. Small for gestation age was more in the NPCC.

Medium (The baseline characteristics in relation to the vasculopathy are different. No blinding for the outcome assessment).


Herman 1999 [22](USA)

24 women with type I diabetes who attended the preconception clinic, and 74 women with type I diabetes who did not attend the preconception clinic.

PCC included education, counseling, glycemic control, and assessment of complications of diabetes such as nephropathy and retinopathy

Women who had PCC had significantly more spontaneous abortion, significantly lower level of HA1C at booking and throughout pregnancy and significantly heavier infants at birth than NPCC group (p < 0.05). There was no significant difference between the two groups in the frequency of infants with congenital malformations, gestation age at delivery or frequency of neonatal admission to the intensive care unit.

High (The study was not designed to assess the clinical outcomes of the preconception care but the differences in the socio-demographic features between the groups who attend the preconception care and those who did not. The target level for the glycemic control was not clear and the absolute level of Hb A1C at booking and all through pregnancy for the study and the control groups was not mentioned)


Jaffiol 2000 [23](France)

21 IDDM attended the pre-conception care and 40 did not attend

PCC included education, glycemic control self monitoring of blood glucose and Contraception

The investigated outcomes included polyhydramninos, pre-eclampsia, premature deliver, rate of cesarean section, rate of spontaneous and therapeutic abortion, perinatal and neonatal mortality, neonatal hypoglycemia and birth trauma. Significant reduction in the total fetal loss, neonatal mortality and congenital malformations (p < 0.05), the level of maternal HA1C in the 1st trimester (p < 0.05) and total adverse obstetrics complications (p < 0.05)

Low (good report, clear intervention description, the comparative groups received same antenatal intervention. No blinding for outcome assessment)


Jensen 1986 [24](Denmark)

9 women with insulin dependent diabetes had preconception care and 11 women with insulin dependent diabetic who did not receive preconception care.

PCC included continuous insulin infusion initiated 2 months prior to conception

No significant difference in congenital malformations and HA1C level, between the two groups

High (small number of study and control group, many differences in the baseline characteristics in the severity of diabetes, 5 of the 11 control women were treated in the diabetic clinic in the hospital before pregnancy so they knew about the importance of glycemic control both groups have the same HA1C levels in early pregnancy)


Kitzmiller 1991[25](USA)

84 women in preconception care and 110 women had no preconception care

PCC included glycemic and dietary control education, exercise and contraception.

The frequency of congenital abnormalities in the PCC group was 1.2% compared to 10.9% in the NPCC group (p < 0.05). There were 12 spontaneous abortion in the preconception care group and 14 in the group who received no preconception care.

Low (good report clear methodology)


Rosenn 1991[26](USA)

28 women in the preconception group and 71 in the control group

PCC included dietary advice and glycemic control

HA1C concentration in the PCC group was lower than in the NPCC group (p < 0.0008). Spontaneous abortion rate was lower (p < 0.04) and there was no congenital malformations in either group.

Medium (52% of preconception care patients dropped out, no blinding in the assessment of the outcome)


Temple 2006a [10]2006b [29](UK)

110 women with type I diabetes attended the preconception care clinic and 180 women with type I diabetes did not attend the preconception care clinic

PCC included: Glycemic control, folic acid supplementation, smoking cessation, education.

There was significant improvement in the outcome between the PCC group and the NPCC group in the rate of spontaneous abortion (p < 0.056) and in the rate of preterm delivery (p < 0.02). The rate of congenital malformations was lower in PCC group compared to the NPCC group (p < 0.065). the adverse outcome including malformations, still birth and neonatal death were significantly more in the latter group than the former one (p < 0.026)

Low (Baseline characteristics in both groups were similar; the prospective nature of the study ascertained the completeness of the follow up, the completeness of the baseline and the outcome data. Use of appropriate statistical tests such as logistic regression analysis confirmed the association between the preconception care and outcomes).


Willhoite 1993[30](USA)

62 women with either type I or type II diabetes who received preconception counseling and 123 women with either type I or type II diabetes who did not receive preconception counseling

PCC included counseling by health professional the control group received no counseling.

PCC group had significantly less perinatal mortality than the NPCC group (OR3.9 CI 1.2-13.9) and insignificantly less congenital malformations (OR 4.2 CI 0.5-29.7)

High (Base line characteristics of the two groups were significantly different in age, duration of diabetes and smoking all are confounding factors for the outcomes. The two groups did not receive the same antenatal intra-partum and postnatal care. The assessor of the congenital malformation was not blinded)


Boulot 2003 [33](France)

172 women with either type I or type II diabetes who received PCC and 260 women with either type I or type II diabetes who did not receive PCC

PCC included education, assessment of diabetes complications glycemic control self monitoring of blood glucose and Contraception

PCC group had significantly less perinatal mortality than the NPCC group, (p < 0.005) for type 1 diabetics and significantly less congenital malformations, (p < 0.005) for type 1 diabetics

Low (cases and control were well defined and comparable, selection bias is unlikely as consecutive cases were enrolled, the prospective nature of the study ascertained the completeness of the follow up, the completeness of the baseline and the outcome data)


Galindo 2006 [32](Spain)

15 women with pre-existing diabetes received PCC and 112 women with pre-existing diabetes did not receive PCC.

PCC included education, glycemic control self monitoring of blood glucose

The frequency of congenital abnormalities in the PCC group was 3/15 compared to 14/112 in the NPCC group. There was 1 spontaneous abortion in the PCC group and 9 in the group who received no PCC.

Low (cases and control were well defined and comparable, selection bias is unlikely as consecutive cases were enrolled, the prospective nature of the study ascertained the completeness of the follow up, the completeness of the baseline and the outcome data)


Garcia Ingelmo 1998 [34](Spain)

12 women with pre-existing diabetes received PCC and 12 women with pre-existing diabetes did not receive PCC

PCC glycemic control.

The frequency of congenital abnormalities in the PCC group was 3/12 compared to 2/12 in the NPCC group. In the PCC 6/12 neonates were macrosomic while 4/12 were macrosomic in the NPCC group. HbA1c was significantly lower in the first trimester in the PCC group compared to the NPCC group , (p < 0.01)

High (Both the study population and the control were not representative of the general diabetic population with frequency of diabetic vascular complications approaching 50%. The PCC components were not defined neither the target blood glucose)


Key: HbA1c = Glycosylated Hemoglobin A, PCC = Preconception Care, NPCC = No Preconception Care, OR = Odd Ratio, IDDM= Insulin depended Diabetes Miletus, CI = Confidence Interval

Wahabi et al. BMC Pregnancy and Childbirth 2010 10:63   doi:10.1186/1471-2393-10-63

Open Data