I'm 30 weeks pregnant with bad back and

Call your OB's on-call line now, before you fill the tub — new back and belly pain at 30 weeks is something they should hear tonight, and the two-hour soak is the piece to drop first.

If any of these is happening while we talk — bleeding or leaking fluid, regular period-like tightenings, pain that is severe or stays constant, the baby moving much less than usual, a bad headache with blurred vision, pain high under your ribs, or feeling faint — call your local emergency number now and go in to the maternity unit or emergency department, and do not wait for the on-call line to call back. Tell them you are 30 weeks pregnant and how many weeks, in the first sentence.

1) The soak you planned, and what to do instead

Why I would not run tonight's plan. The NHS patient page I checked today, "Is it safe to use a sauna or jacuzzi if I'm pregnant?", says plainly: "You may choose to avoid them because of the risks of overheating, dehydration and fainting," because in a hot tub or jacuzzi your body cannot lose heat by sweating, so your core temperature rises; on water temperature it says: "If you're using a hydrotherapy pool, the temperature should not be above 35C. Some hot tubs can be as hot as 40C, so it's best to avoid them." Your 90–96°F is right up against that line and then some. Add two hours in water, a 30-week belly, and the fact that nobody has assessed this pain yet, and the bath is the wrong first move — it can make you faint, it is a fall risk getting in and out, and it delays the call that matters.

What is on the same list, in order, all tonight-able:

1. Call the on-call line first. Ten minutes on hold while the water fills costs nothing.
2. Warm shower, 10 minutes, standing with a hand on the wall. This is the closest thing to the relief you wanted, and it is the lowest-risk way to get it.
3. If and only if they say a bath is fine: shallow, warm, short. Check the thermometer before you get in, keep it to about 10–15 minutes not two hours, keep a hand on the edge, have your partner within earshot, and get out slowly. If you feel flushed, sweaty, lightheaded or sick, get out and cool down.
4. Heat on the back, not the belly. Heating pad on the lowest setting, a thick towel between it and your skin, 15–20 minutes, then off. Not on the belly, and never to sleep on.
5. Support belt on for the moving parts of the evening — cooking, school run, stairs. Loosen it the moment it feels like pressure rather than support.
6. Position changes beat position. Side-lying with pillows between knees and under the belly, or sitting back with feet up, and change every 20–30 minutes.
7. Fluids and small food already at home. Water through the evening and something with protein in it, because empty and overheated feels exactly like cramping.

2) Keep and avoid tonight

Keep: the on-call call, the shower, the low heat on the back, the belt, side-lying, water, small snacks, your partner home.

Avoid: the two-hour soak and any temperature above what your thermometer reads on a warm setting; lying flat on your back for long stretches; the heating pad on your belly or overnight; the pool pass this weekend until the OB has looked at you and said water is fine; anything you would take for the pain that is not already prescribed to you, and any new painkiller, supplement or powder anyone suggests — including things sold as "pregnancy safe" or bought online; any bath salt, oil or additive you have not used before.

3) Red flags — stop the home plan and get seen

Go now, do not wait for morning:

• any vaginal bleeding, or leaking fluid
• regular tightenings or period-like cramping, even if they ease
• belly pain that is severe, or stays constant, or changes the shape of your belly
• the baby moving much less than usual, or not at all
• bad headache with blurred or flashing vision, pain high under the right ribs, sudden puffiness of face or hands
• fast or difficult breathing, chest pain, one calf painful and swollen
• feeling faint, collapsed, or too weak to get out of bed
• fever with belly pain

If none of those: the plan is still the on-call call tonight, not the tub.

Say it like this to the on-call nurse (screenshot this): "I'm 30 weeks pregnant. I've had bad lower back and belly pain since [time]. It is [constant / comes and go]. No bleeding, no leaking. The baby is moving [as usual / less]. Warm water is the only thing that helps. I was about to soak but didn't. What do you want me to do tonight, and what should bring us in?"

What success looks like in the next 24 hours — not a cure, just the goal: the on-call line has told you whether this needs to be seen tonight, you have a named threshold for what would change that, your pain has a safer ritual around it (shower, low back heat, side-lying) instead of a two-hour tub, and if you do get seen, you arrive with the timing, the movement pattern and the pregnancy record in your hand.

One question, because it changes tonight's plan: is the pain constant, or does it come in waves with tightening — and alongside it, any bleeding, leaking, or a change in the baby's movements? Also, which country or city are you in, so I can point you at the right local door.

I can't tell from here what this pain is, and that is not a gap I can close from a chat — only your OB, the midwife or the maternity team can examine you and decide. This is not a diagnosis, and I am not changing anything you take; the on-call line decides that.

If you tell me your country or city, I can look up the local maternity unit and its 24-hour line for you.

Source: nhs-conditions https://collingwoodsurgery.nhs.uk/new-york/common-questions/pregnancyis-it-safe-to-use-a-sauna-or-jacuzzi-if-i-am-pregnant