Maternal Plasma/Urine/Hair/Amniotic Fluid Levels of Selected Trace Elements and Heavy Metals in Pregnancies Complicated With Neural Tube Defects
Conditions: Neural Tube Defects
Sponsor: Cengiz Gokcek Women's and Children's Hospital

Full study protocol and statistical 
analysis plan 
Official Title of the study: 
Maternal plasma/urine/hair/amniotic fluid levels of selected trace elements and heavy metals in 
pregnancies complicated with neural tube defects  
Date of the document: 
August 2020. 
Contents: 
1. Participant Flow 
2. Baseline Characteristics 
3. Outcome Measures 
4.Endpoints of the study 
5.Limitations and Strengths 
6. Certain Agreements 
7. Results Point of Contact  
 
1. Participant Flow 
Recruitment Details 
This observational case-control study will be conducted at the Department of Obstetrics and 
Gynecology, Cengiz Gokcek Public Hospital, Gaziantep, Turkey, between August 2020 and 
March 2021. The protocol was approved by the Ethics Committee for Clinical Research of 
Gaziantep University (reference no: 2020/167). The study strictly will be adhered to the 
principles of the Declaration of Helsinki. All subjects will be included in the study gave oral 
and written informed consent. 140 women were enrolled in the study in two groups.  
Pre‐assignment Details 
The authors first will be assessed the recruited people to ensure meeting the inclusion and 
exclusion criteria. The inclusion criteria will be made according to the official documents. 
Arm/Group Information * 
 
There are two groups in the study. 
 
Arm/Group Title * 

 
Neural tube defect group 
Control group 
2. Baseline Characteristics 
To detect significant difference between groups according to lead levels with a moderate 
effect size (Cohen's d =0.53), minimum required sample size was estimated as 45 for each 
group (α=0.05, 1-β=0.80). Power analysis was performed by using G power package version 
3.1. Kolmogorov Smirnov and Shapiro Wilk tests will be used to test the normal distribution 
of data. For comparing groups (NTD/control) the student t-test will be used for variables that 
have a normal distribution, and the Mann Whitney U test will be used for variables that have 
not a normal distribution. The ROC analysis will be applied for the determination of cut-off 
point for variables. Moreover, Spearman correlation test will be used for the relationship of 
between variables. SPSS for Windows 22.0 and Medcalc programs will be used for statistical 
analysis. p<0.05 will be accepted as statistical significance.  
 
3. Outcome Measures 
 
Primary Outcome Measures : folic acid, zinc (Zn), molybdenum (Mo), vanadium (V), 
strontium (Sr), aluminum (Al), tin (Sn), antimony (Sb), mercury (Hg), calcium (Ca), iron ( 
Fe), magnesium (Mg), phosphorus (P), barium (B) and selenium (Se) concentrations  
Secondary Outcome Measures:  
The elements and vitamins concentrations in the spinal NTD group and the cranial NTD 
group. 
 
 
 
4. Endpoints of the study:  
The primary outcome in these analyses will compare folic acid, zinc (Zn), molybdenum (Mo), 
vanadium (V), strontium (Sr), aluminum (Al), tin (Sn), antimony (Sb), mercury (Hg), calcium 
(Ca), iron (Fe), magnesium (Mg), phosphorus (P), barium (B) and selenium (Se) 
concentrations in NTD group and control group. 
 
5.Limitations and strengths: 
Our study has some strengths. These metals will be measured blood, urine and hair samples. So, 
these measurements may not reflect the metals exposure levels only recent exposure and will reflect 
before and during pregnancy.  

 
6. Certain Agreements 
 
This work will be supported by the Scientific Research Project Fund of Yozgat Bozok University. 
 
7. Results Point of Contact 
Corresponding Author: Ali Ovayolu, Department of Obstetrics and Gynecology, Cengiz 
Gokcek Women's and Children's Hospital, Gaziantep, Turkey, drovayolu@yahoo.com 
Address: Osmangazi Mahallesi, Cengiz Gokcek Kadın Hastaliklari ve Dogum Hastanesi, 
27010 Gaziantep, Turkey 
GSM: +90 (532) 640 40 60 
Tel.: +90.342 360 08 88 
Fax: +90.342 360 02 90