Hello and welcome to HCM
You need to know the meaning and importance of the scan report.
It means that the placenta is attached to the posterior wall of the uterus and its lower edge enchroaches the lower uterine segment and reaches upto the opening of the cervix
At 18 weeks she can travel without any harm.
However, you need to get regular ultrasound
of the pelvic region.
This is to know the change in position of the placenta with progressing pregnancy
For a normal vaginal delivery
it should be in the upper uterine segment.
If present in lower uterine segment or near the opening of the cervical lips (cervical os), dilation of the cervix will can cause abrupt separation of the placenta and haemorrhage.
This situation can be prevented by ante-natal diagnosis and caesarean section
But as the pregnancy advances there is groth of both upper and lower uterine segments and the placenta can recede in the upper segment by the time of term.
As for now, there is no harm in travelling. Light aerobic exercises permissible in pregnancy can be done.
Thank you and take care
Dr Shailja P Wahal