Page 86 - JCTR-11-2

Journal of Clinical and
Translational Research Crude oil pollutants in Southern Nigeria

2.3. Ethical considerations only 50 crude oil-exposed expectant mothers (and their

The research was conducted in accordance with ethics newborns) and 30 non-exposed expectant mothers
guidelines, and approval was obtained from the Ethics (and their newborns) were finally evaluated, as seven
and Health Research Committee of the Central Hospital, participants had incomplete data.
Warri, Delta State, Nigeria (CHW/ECC VOL 1/168). 2.7. Sample collection
Before collecting specimens, informed consent was given
by all participants. Participants who did not provide Venous blood samples (approximately 5 mL) were
informed consent were excluded. Absolute confidentiality obtained from expectant mothers during the gestational
was maintained throughout the study. period of 29 – 39 weeks and subsequently transferred into
a sterile sample container. The specimens were allowed
2.4. Inclusion and exclusion criteria to coagulate at a temperature range of 20 – 22°C. Upon

The study only included healthy expectant mothers who completion of the coagulation process, the samples
gave birth in the hospital, attended the antenatal clinic for were subjected to centrifugation in a bucket centrifuge
care, and delivered their babies there. Expectant mothers operating at 3,000 rpm for 10 min. The resulting serum
who had lived in Warri South, the location of crude oil was carefully decanted into a new container and stored
search and extraction, permanently for more than 5 years at −80°C until further analysis. Following childbirth, the
were also included. The control subjects were permanent umbilical cord was immediately clamped at both ends and
residents of Asaba town who had never resided in Warri severed. Approximately 5 mL of cord blood was extracted
town or any other community where crude oil extraction from the umbilical vein and placed into a designated plain
takes place. Women who were expecting and had container, which was then properly labeled. The collected
complex obstetric problems, hemoglobinopathies, thyroid cord blood samples were allowed to clot and subsequently
abnormalities, or chronic disease were not included. centrifuged at 2,500 rpm for 15 min after clot retraction.
The serum was decanted and preserved at −80°C until
2.5. Questionnaire further analysis.
To collect socio-anthropological data, an interview- 2.8. Determination of thyroid hormones and
administered questionnaire was employed, which included thyroid-stimulating hormone (TSH)
age, educational status, medical history, and family
history of hypothyroidism. The hospital records provided Enzyme-linked immunosorbent assay test kits
information on medication use, due date of delivery, (Elabscience, United States of America [USA]) were used
and maternal health and obstetrics. Anthropometric for the determination of thyroid hormones. Measuring
the concentration of hormones in the blood is considered
measurements (birth weight, head circumference, a useful method for diagnosing thyroid problems. The
and recumbent length in the newborns) were made reagents, calibrators, and controls were equilibrated to
using standard procedures. PI was derived for all study room temperature, specifically between 20°C and 27°C.
individuals using Equation I:
The wells of the microplates were arranged in duplicate
Birthweight(g) for each calibrator, control, and patient specimen to be
Ponderal index = × 100 (I)
Birthlength(cm) analyzed. The hormone levels were determined in batches
according to the manufacturer’s protocol, using 1 mL
A PI < 10 indicates fetal malnutrition, while a PI < 3 serum aliquot, which was kept frozen at −80°C. The serum
suggests severe fetal wasting. 14 aliquot was allowed to thaw at room temperature before
analysis.
2.6. Sample size determination
To avoid differences in reaction time between wells, the
The sample size (N) was obtained using Equation II: 15 reagents were added in the same sequence. The plate was not
N=Z P(1-P)/d 2 (II) shaken after adding the substrate. The incubation process
2
Where N = required sample size, Z = confidence level occurred at ambient temperature for 15 min. The optical
interval at 95% (standard value of 1.96), P = prevalence density in each well was measured at a wavelength of 450 nm
of newborn deaths due to crude oil spillage in using a microplate reader. The absorbance was measured
Niger Delta, Nigeria, and d = margin of error at 5% within 30 min after the addition of the stop solution.
(standard value of 0.05). The rate of newborn death due A calibration curve was utilized to determine the
to crude oil spillage in the Niger-Delta region of Nigeria hormone levels in the specimens. The concentration for an
was 3.83%. The sample size was calculated to be 56.59. unknown sample was estimated by extrapolating from the
16
Therefore, 57 expectant mothers were enrolled. However, graph. 17,18

Volume 11 Issue 2 (2025) 80 doi: 10.36922/jctr.24.00083