The culturing human embryo in vitro is a process of myriad contributing elements. From these factors is the pH of embryo culture media, which is crucial for embryo development. The investigators plan to examine three different pH values of the culture media on the live birth rate of in vitro cultured human embryos.

In vitro fertilisation laboratory is the black box in which early human embryo development of infertile couple occurs. This laboratory holds many variables such as incubator type, air quality, brands of culture media, culture temperature and the pH of culture medium. Despite the importance of the culture medium pH, there is no single RCT has examined its effect on live birth rate post in vitro fertilisation. The investigators of this study believe that leaving this crucial element to the wishes of large companies and media designers is unwise. This RCT aims to provide a conclusive answer on pH effect on live birth rate of in vitro cultured human embryos.

Inclusion Criteria:

1. Women age of ≥ 18 to ≤ 40
2. BMI of ≤ 35 (After approval of the DMC on 19 Feb 2021 and the IRB thereafter, BMI is changed from ≤31 to ≤35 based on clinician request. DMC).
3. Normal responder (≥ 10 antral follicle count (AFC) during basal ultrasound examination)
4. PCOS
5. Women who have ≥ 1 year of primary or secondary infertility
6. Tubal factor (unilateral, bilateral obstruction or salpingectomy)
7. Normal semen parameters
8. Male factor: oligoasthenozoospermia or obstructive azoospermia
9. Women who are undergoing their first IVF or ICSI cycle or second IVF Cycle with previous successful attempt
10. Women who will undergo only fresh embryo transfer
11. Women who have normal endometrial thickness (> 7 mm) and echo-pattern at the time of hCG trigger
12. Women who have normal transvaginal ultrasound during the follicular phase (defined as no intra cavity pathology; e.g. submucousal myomas, polyps or septa)

Exclusion Criteria:

1. Women who had unilateral oophorectomy
2. Women who had uterine pathology or abnormality
3. Women or their husbands who had abnormal karyotyping
4. Women with history of recurrent abortions or repeated implantation failures
5. Women who had uncontrolled diabetes
6. Women with diagnosed or undiagnosed liver or renal disease
7. Women who had a history of severe ovarian hyperstimulation
8. Women who had history of malignancy or borderline pathology
9. Women who will not meet the inclusion criteria
10. Women who will refuse to participate in the study
11. Women with endometriosis
12. Patient undergoing PGS or PGD
13. Severe male factor and non-obstructive azoospermia.